Co-reporter:Panpan Yang, Qineng Xia, Xiaohui Liu, Yanqin Wang
Fuel 2017 Volume 187() pp:159-166
Publication Date(Web):1 January 2017
DOI:10.1016/j.fuel.2016.09.026
•High yield production of DMF from HMF is realized over NiCo/C catalyst through CTH process.•Formic acid is an excellent hydrogen donor in DMF production.•A reaction route involving 5-methylfurfural instead of 2,5-bis(hydromethyl)furan as an intermediate in provided.Catalytic transfer hydrogenation/hydrogenolysis of 5-hydroxymethylfurfural (HMF) to valuable chemicals, 2,5-dimethylfuran (DMF), is realized over a carbon supported nickel-cobalt catalyst with formic acid as hydrogen donor. The highest DMF yield, 90.0%, is achieved at 210 °C under self-generated pressure. A reaction route involving 5-methylfurfural (5-MF) instead of 2,5-bis(hydromethyl)furan (BHMF) as an intermediate has been investigated, which is different from that when H2 is used as hydrogen source in previous reports. The influence of the amount of formic acid is investigated on the conversion of HMF and the yield of DMF. The effectiveness of this strategy has also been used for the conversion of furfural to 2-methylfuran, another valuable chemicals.
Co-reporter:Xuewang Han;Chaoqun Li;Xiaohui Liu;Qineng Xia;Yanqin Wang
Green Chemistry (1999-Present) 2017 vol. 19(Issue 4) pp:996-1004
Publication Date(Web):2017/02/21
DOI:10.1039/C6GC03304K
The selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) has attracted much attention recently, as FDCA could be used as a polymer precursor to produce recyclable bio-based polymers. But most studies focused on the design of noble metal catalysts for the efficient oxidation of HMF to FDCA, here, non-noble metal catalysts, MnOx–CeO2 mixed oxides, were prepared by a co-precipitation method and used in the direct aerobic oxidation of HMF to FDCA. As high as 91% yield of FDCA was achieved over the MC-6 (Mn/Ce = 6) catalyst and the catalyst can be reused five times without much loss of catalytic activity, this is the best result for non-noble metal catalyzed HMF oxidation to FDCA in the aqueous phase. Structural analysis revealed that surface Mn4+ ions are the active sites and play key roles for the oxidation of HMF in the absence of noble metals. In addition, the reaction mechanism over the MnOx–CeO2 catalyst was also proposed based on the synergistic interaction between Mn and Ce oxides.
Co-reporter:Jianjian Wang;Jinxu Xi;Qineng Xia;Xiaohui Liu;Yanqin Wang
Science China Chemistry 2017 Volume 60( Issue 7) pp:870-886
Publication Date(Web):10 May 2017
DOI:10.1007/s11426-016-9035-1
With concerns of diminishing fossil fuel reserves and environmental deterioration, great efforts have been made to explore novel approaches of efficiently utilizing bio-renewable feedstocks to produce chemicals and fuels. 5-Hydroxymethylfurfural (HMF), generated from dehydration of six-carbon ketose, is regarded as a primary and versatile renewable building block to realize the goal of production of these high valued products from renewable biomass resources transformation. In this review, we summarize the recent advances via green routes in the heterogeneous reaction system for the catalytic production of HMF from glucose conversion, and emphasize reaction pathways of these reaction approaches based on the fundamental mechanistic chemistry as well as highlight the challenges (such as separation and purification of products, reusing and regeneration of catalyst, recycling solvent) in this field.
Co-reporter:Tianye Guo, Qineng Xia, Yi Shao, Xiaohui Liu, Yanqin Wang
Applied Catalysis A: General 2017 Volume 547(Volume 547) pp:
Publication Date(Web):25 October 2017
DOI:10.1016/j.apcata.2017.07.050
•A new route is reported for the HDO of lignin model compounds to arenes via hydrogen transfer.•The reaction pathways study shows that the DDO reaction was the main pathway.•5%Ru/10%Nb2O5/SiO2 catalyst showed excellent hydrothermal stability.A new route is reported for the direct deoxygenation of lignin model compounds to aromatic hydrocarbons via the catalytic hydrogen transfer reactions over Ru/Nb2O5-SiO2 catalyst with 2-PrOH as a hydrogen donor. It is found that Ru/Nb2O5-SiO2 catalyst is active for the hydrodeoxygenation of p-cresol with 98.5% conversion and 84.0% yield of toluene at 230 °C, owing to the significant promotion effect of NbOx species on CO bond cleavage and the proper transfer hydrogenation activity of Ru. Furthermore, Ru/Nb2O5-SiO2 catalyst also shows excellent performances in the transfer hydrodeoxygenation of various lignin model compounds such as 2-methoxy-4-methyl phenol, benzyl phenyl ether (α-O-4 model compound), 2-(2-methoxyphenyl)oxy-1-phenethanol (β-O-4 model compound) and even the real lignin extracted from birch, into aromatic hydrocarbons with 2-PrOH as the hydrogen donor. The reaction pathway studies of these model compounds demonstrate that the direct deoxygenation (DDO) is the main reaction route over Ru/Nb2O5-SiO2 catalyst in the presence of 2-PrOH. Here, using 2-PrOH as a hydrogen source is found to be more selective to aromatic hydrocarbons than using molecular hydrogen. This work provides a new way for the high selective production of aromatic hydrocarbons from renewable lignin via the catalytic hydrogen transfer reactions.Download high-res image (194KB)Download full-size image
Co-reporter:Xuewang Han, Liang Geng, Yong Guo, Rong Jia, Xiaohui Liu, Yongguang Zhang and Yanqin Wang
Green Chemistry 2016 vol. 18(Issue 6) pp:1597-1604
Publication Date(Web):06 Nov 2015
DOI:10.1039/C5GC02114F
Base-free aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) was realized successfully based on the design of a novel Pt/C–O–Mg catalyst. The properties of this catalyst were characterized using TEM, XRD, XPS and temperature-programmed desorption of CO2. The catalyst had excellent activity and stability, the yield of FDCA reached 97% under optimal conditions (110 °C, O2 1.0 MPa) and the catalyst was used ten times with little loss of activity. The excellent activity and stability may come from the formation of a C–O–Mg bond, which created new, strong and stable basic sites. Further scaling up the reaction by 20 times, the yield of isolated FDCA reached 74.9% with very high purity (99.5%). This FDCA would be used as a substitute of the polymerization monomer for polyethylene terephthalate plastic (PET) synthesis after purification.
Co-reporter:Hong Yang, Xiaohui Liu, Guanzhong Lu, Yanqin Wang
Microporous and Mesoporous Materials 2016 Volume 225() pp:144-153
Publication Date(Web):1 May 2016
DOI:10.1016/j.micromeso.2015.12.017
•SAPO-34 nanoplates are synthesized via hydrothermal treatments.•The obtained SAPO-34 nanoplates poss a uniform size with the thickness of 40–50 nm.•PEG, as intra-crystalline mesoporous porogens, has little impact on the morphology of SAPO-34.•Nanoplate-like SAPO-34 shows higher catalytic activity than cube-like SAPO-34.In this work, SAPO-34 nanoplates were synthesized by dissolving pseudoboehmite and silica sol in an aqueous solution of tetraethyl ammonium hydroxide (TEAOH) firstly, then adding H3PO4 in the above mixture, and finally following with hydrothermal treatment. SEM and TEM observations showed that the SAPO-34 nanoplate possed a uniform size (200–400 nm) with the thickness of 40–50 nm. Detailed analysis revealed that the dissolution or depolymerization of the silica sol in alkaline conditions was critical for the formation of SAPO-34 nanoplates. Furthermore, PEG was introduced during the synthesis process as porogens and mesoporous SAPO-34 nanoplates were obtained without disturbing the formation of nanoplates. The catalytic properties of SAPO-34 were tested in the dehydration of fructose into 5-hydroxymethylfurfural (HMF). All the nanoplate catalysts showed excellent catalytic performance compared with conventional cube-like SAPO-34, and the mesoporous structure could further facilitate mass transfer.SAPO-34 nanoplates with the thickness of 40–50 nm were successfully synthesized by mixing precursors in different sequence and then hydrothermally treated for crystallization.
Co-reporter:Chunrui Li;Daqian Ding;Qineng Xia;Xiaohui Liu ; Yanqin Wang
ChemSusChem 2016 Volume 9( Issue 13) pp:1712-1718
Publication Date(Web):
DOI:10.1002/cssc.201600386
Abstract
Synthesis of branched long-chain alkanes from renewable biomass has attracted intensive interest in recent years, but the feedstock for this synthesis is restricted to platform chemicals. Here, we develop an effective and energy-efficient process to convert raw lignocellulosic biomass (e.g., corncob) into branched diesel-range alkanes through three tandem steps for the first time. Furfural and isopropyl levulinate (LA ester) were prepared from hemicellulose and cellulose fractions of corncob in toluene/water biphasic system with added isopropanol, which was followed by double aldol condensation of furfural with LA ester into C15 oxygenates and the final hydrodeoxygenation of C15 oxygenates into branched long-chain alkanes. The core point of this tandem process is the addition of isopropanol in the first step, which enables the spontaneous transfer of levulinic acid (LA) into the toluene phase in the form of LA ester through esterification, resulting in LA ester co-existing with furfural in the same phase, which is the basis for double aldol condensation in the toluene phase. Moreover, the acidic aqueous phase and toluene can be reused and the residues, including lignin and humins in aqueous phase, can be separated and carbonized to porous carbon materials.
Co-reporter:Qineng Xia, Yinjiang Xia, Jinxu Xi, Xiaohui Liu and Yanqin Wang
Green Chemistry 2015 vol. 17(Issue 8) pp:4411-4417
Publication Date(Web):15 Jul 2015
DOI:10.1039/C5GC01119A
An energy-efficient catalytic system for the one-pot production of 1-octanol from biomass-derived furfural-acetone (FFA) under mild conditions in water was developed, by sequential hydrogenation/hydrogenolysis over a hydrophilic Pd/NbOPO4 catalyst. A strategy of creating an intentional “phase problem” has been employed to prevent the over-hydrogenolysis of 1-octanol into n-octane and therefore increased the selectivity to 1-octanol. The effects of reaction conditions as well as a variety of noble-metal loaded bifunctional catalysts have been systematically investigated to maximize the yield of 1-octanol. Moreover, the addition of liquid acids to the catalytic system further enhanced the selectivity towards the formation of 1-octanol. There is a strong correlation between the acid strength of an acidic additive and the sum yield of 1-octanol and octane. With the addition of TfOH, the highest yield of 1-octanol (62.7%) was obtained from one-pot conversion of biomass-derived FFA over Pd/NbOPO4.
Co-reporter:Daqian Ding, Jinxu Xi, Jianjian Wang, Xiaohui Liu, Guanzhong Lu and Yanqin Wang
Green Chemistry 2015 vol. 17(Issue 7) pp:4037-4044
Publication Date(Web):12 Jun 2015
DOI:10.1039/C5GC00440C
The alcoholysis of cellulose into methyl levulinate (ML) in methanol media was investigated in the presence of several kinds of acid catalyst. One of the synthesized solid niobium-based phosphate catalysts was found to be highly efficient for the generation of ML, reaching an ML yield as high as 56%, higher than the LA yield (52%) in aqueous solution with the same reaction conditions as those used in our previous study (Green Chem., 2014, 16, 3846–3853). More interestingly, in water, very strong Lewis acid promoted the formation of LA; but in methanol, Brönsted acid enhanced the formation of ML. In-depth investigation showed that the mechanism and type of intermediates of cellulose alcoholysis in methanol were different from those in water and a high Brönsted/Lewis acid ratio (known as B/L acid ratio) of solid catalysts is needed to prevent the generation of by-products, namely, methyl lactate and 1,1,2-trimethoxyethane. This new-proposed reaction mechanism affected by the B/L acid ratio was very helpful for the design of efficient catalysts.
Co-reporter:Jianjian Wang, Jinxu Xi and Yanqin Wang
Green Chemistry 2015 vol. 17(Issue 2) pp:737-751
Publication Date(Web):08 Dec 2014
DOI:10.1039/C4GC02034K
Recently, research on the catalytic production of glucose, the first platform chemical in biorefinery, has become attractive in catalysis studies and the chemical/fuel industry owing to its broad applications. It opens up a new route for achieving sustainable chemical production and energy supply. From this viewpoint, this contribution attempts to overview the recent advances in the catalytic routes for the synthesis of glucose from lignocellulosic biomass over various homogeneous and heterogeneous catalysts.
Co-reporter:Daqian Ding, Jianjian Wang, Jinxu Xi, Xiaohui Liu, Guanzhong Lu and Yanqin Wang
Green Chemistry 2014 vol. 16(Issue 8) pp:3846-3853
Publication Date(Web):19 Jun 2014
DOI:10.1039/C4GC00737A
Direct catalytic conversion of cellulose to levulinic acid (LA) by niobium-based solid acids and further upgrading to γ-valerolactone (GVL) on a Ru/C catalyst were realized through sequential reactions in a reactor. Firstly, using aluminium-modified mesoporous niobium phosphate as a catalyst, cellulose can be directly converted to LA with as high as 52.9% yield in aqueous solution, even in the presence of the Ru/C catalyst. To the best of our knowledge, this is the best result over a heterogeneous catalyst so far. It was found that the type of acid (Lewis and Brønsted acids) and acid strength had an influence on the yield of LA; the doping of aluminium can enhance the strong Lewis and Brønsted acids, especially the strong Lewis acid, thus resulting in the increase of LA yield from cellulose as well as from glucose and HMF. Such an enhancement by a Lewis acid on LA yield from HMF was further confirmed by adding lanthanum trifluoroacetate [(TfO)3La], a strong Lewis acid, in the catalytic system (HCl, (TfO)3H, niobium phosphate), indicating that a suitable ratio of Lewis/Brønsted acid is important for higher selectivity to LA from HMF, as well as from cellulose. Then, after replacing N2 with H2, the generated LA in the reaction mixture can be directly converted to γ-valerolactone through hydrogenation over the Ru/C catalyst without further separation of LA.
Co-reporter:Rong Jia, Jiawen Ren, Xiaohui Liu, Guanzhong Lu and Yanqin Wang
Journal of Materials Chemistry A 2014 vol. 2(Issue 29) pp:11195-11201
Publication Date(Web):11 Jun 2014
DOI:10.1039/C4TA01836B
A new type of sulfonated carbon material with amphiphilic properties was synthesized by the hydrothermal carbonization of a mixture of furfural–sodium dodecylbenzene sulfonate at 180 °C in an autoclave. The addition of SDBS is necessary for the production of materials with long carbon chains and is possibly used to improve the solubilization of long carbon-chain and steric compounds such as pivalic acid. The resulting material was characterized by N2 adsorption, XPS, 13C NMR, XRD and FTIR. The synthesized material was proven to be a highly efficient solid-acid catalyst in reactions such as the esterification of pivalic acid with alcohols, and catalytic performance much better than that of conventional solid acid catalysts, e.g. Amberlyst-15 and Nafion resin, was observed.
Co-reporter:Jinxu Xi, Daqian Ding, Yi Shao, Xiaohui Liu, Guanzhong Lu, and Yanqin Wang
ACS Sustainable Chemistry & Engineering 2014 Volume 2(Issue 10) pp:2355
Publication Date(Web):September 2, 2014
DOI:10.1021/sc500380c
The efficient usage of lignocellulosic biomass is of great significance for large-scale low-cost biomass conversion to biofuels and other useful chemicals. Here, an interesting catalytic process was reported related to converting cellulose into ethylene glycol (EG) and ethylene glycol monoether (EGME) in methanol over a Ru/NbOPO4 catalyst, with the cleavage of a C–C bond by NbOPO4 and further hydrogenation by supported Ru particles. The influence of reaction temperature, hydrogen pressure, and reaction time was systematically investigated and showed that a 54.5% total yield of EG and EGME could be obtained at 220 °C in 3 M Pa H2, which was an exciting result. Meanwhile, the effect of solvent was also studied in detail. It was shown that methanol played an important role in the production of EG and EGME, especially in the cleavage of the C–C bond. Methanol could protect the C═O bond in glucose produced from cellulose through acetalization, thus prevent its hydrogenation, and led to the production of EG and EGME. Furthermore, the influence of dopants (W, Sn, Ni, Cu) was further investigated, and it was found that only the Ru–Ni/NbOPO4 catalyst was more effective through limiting the further hydrogenolysis of products (EG and EGME) to CO and alkanes, and as high as 64% total yield of EG+EGME was achieved. Moreover, the Ru–Ni/NbOPO4 catalyst showed good reusability, which can be reused at least four times with a little loss in EG and EGME yield.Keywords: Cellulose; Ethylene glycol; Hydrogenation; Methanol; Ru/NbOPO4;
Co-reporter:Jianjian Wang, Xiaohui Liu, Bicheng Hu, Guanzhong Lu and Yanqin Wang
RSC Advances 2014 vol. 4(Issue 59) pp:31101-31107
Publication Date(Web):22 Jul 2014
DOI:10.1039/C4RA04900D
Efficient production and sequential utilization of furan derivatives will provide a promising approach towards achieving renewable liquid biofuels from biomass. This study aims to investigate the simultaneous production of furfural and 5-(hydroxymethyl)furfural (HMF) from biomass and further upgrade them into biofuels. Firstly, furfural and HMF are obtained together with high yields from a mixture of C5 (xylose) and C6 (glucose) sugars, or from lignocellulosic biomass, such as birch, cornstalk, pine, bagasse, and poplar in a tetrahydrofuran (THF)/H2O–NaCl biphasic system under mild conditions. The co-existence of C5/C6 sugars or impurities in lignocellulosic biomass has little influence on the simultaneous production of furfural and HMF. Then, the generated furfural and HMF in the upper organic phase are directly used as substrates without extra separation and purification processes, and efficiently upgraded to 2-methylfuran (MF) and 2,5-dimethylfuran (DMF), both of which are considered as promising renewable liquid biofuels with high-energy content. Hence, the seamless integration of lignocellulosic biomass into renewable liquid biofuels will accelerate our society moving towards a renewable transportation economy by utilizing cheap feedstocks, mild reaction conditions, and cost saving in separation and purification.
Co-reporter:Qi-Neng Xia;Qian Cuan;Xiao-Hui Liu; Xue-Qing Gong; Guan-Zhong Lu ; Yan-Qin Wang
Angewandte Chemie International Edition 2014 Volume 53( Issue 37) pp:9755-9760
Publication Date(Web):
DOI:10.1002/anie.201403440
Abstract
Great efforts have been made to convert renewable biomass into transportation fuels. Herein, we report the novel properties of NbOx-based catalysts in the hydrodeoxygenation of furan-derived adducts to liquid alkanes. Excellent activity and stability were observed with almost no decrease in octane yield (>90 % throughout) in a 256 h time-on-stream test. Experimental and theoretical studies showed that NbOx species play the key role in CO bond cleavage. As a multifunctional catalyst, Pd/NbOPO4 plays three roles in the conversion of aldol adducts into alkanes: 1) The noble metal (in this case Pd) is the active center for hydrogenation; 2) NbOx species help to cleave the CO bond, especially of the tetrahydrofuran ring; and 3) a niobium-based solid acid catalyzes the dehydration, thus enabling the quantitative conversion of furan-derived adducts into alkanes under mild conditions.
Co-reporter:Haixiang Tao, Hong Yang, Yanhui Zhang, Jiawen Ren, Xiaohui Liu, Yanqin Wang and Guanzhong Lu
Journal of Materials Chemistry A 2013 vol. 1(Issue 44) pp:13821-13827
Publication Date(Web):07 Oct 2013
DOI:10.1039/C3TA12989F
The sole presence of relatively small micropores in zeolite catalysts strongly influences the mass transfer and catalytic conversion of bulky molecules. Herein, we report a novel synthesis route for the confined synthesis of hierarchical MFI zeolite microspheres with nanorod oriented-assembled structures for the first time via the hydrothermal crystallization of a carbon–silica composite monolith. The growth of such unique zeolite microspheres undergoes a reversed crystal-growth route. Crystallization started on the outer surface of the amorphous particles, then extended to the core and finally resulted in nanorod oriented-assembled structures, due to the confined-space effect of carbon in the carbon–silica monolith. The novel hierarchical zeolite microspheres (5–10 μm), including Silicalite-1, ZSM-5 and TS-1, composed of oriented-assembled nanorods (50–100 nm in width) are easy for separation and have inter-crystalline mesoporous networks between the nanorods; the latter are favourable for mass transfer. More importantly, the hierarchical zeolite microspheres Hier-ZSM-5 and Hier-TS-1 show much higher catalytic activities for bulky substrate conversion than the conventional ZSM-5 and TS-1, respectively. Thus, the novel hierarchical zeolite microspheres reported here show a great potential for industrial applications.
Co-reporter:Jianjian Wang, Jiawen Ren, Xiaohui Liu, Jinxu Xi, Qineng Xia, Yanhong Zu, Guanzhong Lu and Yanqin Wang
Green Chemistry 2012 vol. 14(Issue 9) pp:2506-2512
Publication Date(Web):04 Jul 2012
DOI:10.1039/C2GC35699F
5-Hydroxymethylfurfural (HMF) is a very important intermediate in the fine chemical industry. This study aims to investigate the direct conversion of glucose or glucose-based carbohydrates, such as sucrose, cellobiose, inulin, starch and cellulose, to HMF by using a Sn-Mont catalyst. With the use of this catalyst, a HMF yield of 53.5% was achieved from glucose in a mono-phase medium of tetrahydrofuran (THF)/dimethylsulfoxide (DMSO) at 160 °C for 3 h. The success of one-step conversion of glucose to HMF is attributed to the Sn-Mont catalyst containing two types of acid sites, Lewis acid and Brønsted acid sites. The former one plays a crucial role in the isomerization of glucose to fructose and the latter one is active in the dehydration of generated fructose to HMF. Furthermore, Sn-Mont catalyst also demonstrated excellent activity in the conversion of disaccharides and polysaccharides and as high as 39.1% HMF was directly obtained from cellulose in a THF/H2O–NaCl bi-phasic system.
Co-reporter:Xin Gu, Haixiang Tao, Wolfgang Schmidt, Guanzhong Lu and Yanqin Wang
Journal of Materials Chemistry A 2012 vol. 22(Issue 6) pp:2473-2477
Publication Date(Web):22 Dec 2011
DOI:10.1039/C1JM13400K
Hollow mesoporous aluminosilicate particles have been synthesized through a one-pot synthesis without using any cavity-forming template. The hollow particles have mesoporous shells with surface areas up to 1300 m2 g−1. The thickness of the shell can be adjusted from about 30 nm to 50 nm by tuning the molar Si/Al ratio and/or variation of the time of hydrothermal treatment. EDX analysis (element mapping) revealed a certain zoning of aluminum in the amorphous aluminosilicate particles investigated. There is an enrichment of Al on the outside of the particles close to the surface. The presence of aluminum appeared to be the key factor for the inhomogeneous dissolution of the aluminosilicate (dissolution of silicon-enriched cores) that leads to the formation of hollow particles.
Co-reporter:Yu Zhang, Jianjian Wang, Jiawen Ren, Xiaohui Liu, Xiangcheng Li, Yinjiang Xia, Guanzhong Lu and Yanqin Wang
Catalysis Science & Technology 2012 vol. 2(Issue 12) pp:2485-2491
Publication Date(Web):02 Aug 2012
DOI:10.1039/C2CY20204B
By using cetyltrimethylammonium bromide (CTAB) as the template, a series of mesoporous niobium phosphates were synthesized at different pH values in an aqueous solution. Techniques such as small-angle X-ray diffraction, transmission electron microscopy (TEM) and N2 sorption technique were employed to characterize the mesoporous structures of thus-synthesized materials, EDAX to detect the composition, FTIR and solid state 31P MAS NMR to investigate the framework information, while their acidic properties were analyzed using NH3-TPD and pyridine-FTIR. Samples prepared at neutral to acidic conditions exhibited high surface area (213–297 m2 g−1), narrow pore size distribution (3–4 nm) and a great number of strong Lewis and Brönsted acid sites. These materials exhibited excellent activity in the dehydration of fructose to 5-hydroxymethylfurfural (HMF) in water. The maximum HMF yield reached 45% under 130 °C with a reaction time of 0.5 h and the yield slightly decreased to 32% after five cycles and the five-cycled catalyst can be almost regenerated by calcination at 500 °C with the yield of 40%. The excellent catalytic activity obtained in the aqueous phase can be attributed to its high acid site density and the tolerance to water.
Co-reporter:Wen Lei, Ling-Yi Zhang, Li Wan, Bian-Fang Shi, Yan-Qin Wang, Wei-Bing Zhang
Journal of Chromatography A 2012 Volume 1239() pp:64-71
Publication Date(Web):25 May 2012
DOI:10.1016/j.chroma.2012.03.065
The core–shell silica nanoparticles Fe3O4@SiO2/NH2, wormlike and hexagonal SBA-15 silica were incorporated into polymethacrylate monolithic columns containing butyl methacrylate (BMA) and ethylene dimethacrylate (EDMA), respectively to develop novel stationary phases with mixing mechanism of reverse phase and ion exchange. Experimental conditions including types of nanoparticles, dispersion pattern, nanoparticles concentration, column placement mode, and reaction temperature were optimized for simple and stable column preparation. The poly(BMA-EDMA-Fe3O4@SiO2/NH2) and poly(BMA-EDMA-SBA-15/NH2) (both wormlike and hexagonal shape nanoparticles) monolithic columns were evaluated with mixture of organic acids as sample in capillary electrochromatography (CEC) mode and the relative column efficiency reaches 290,000 plates/m. The results indicate that the incorporation of nanoparticles with various shapes enhances both selectivity and column efficiency due to high specific surface area of nanoparticles and mixing separation mechanism. In addition, poly(BMA-EDMA-Fe3O4@SiO2/NH2) monolith capillary column was applied to separation of aqueous extract of rhizoma gastrodiae and showed great potential in the method development of complex samples.Highlights► Three nanoparticles with different characters were incorporated into monolith. ► Better resolution and high column efficiency up to 290,000 plates/m were achieved. Mixing separation mechanism provides great potential in separation of complex sample. ► The repeatability and long-term stability of new hybrid columns are satisfactory.
Co-reporter:Yong Guo, Xiaohui Liu, Muhammad Usman Azmat, Wenjie Xu, Jiawen Ren, Yanqin Wang, Guanzhong Lu
International Journal of Hydrogen Energy 2012 Volume 37(Issue 1) pp:227-234
Publication Date(Web):January 2012
DOI:10.1016/j.ijhydene.2011.09.111
A Ni-B amorphous alloy catalyst (AP Ni) was prepared and used in an aqueous-phase reforming (APR) of glycerol. Higher stability and higher selectivity towards H2 were obtained when compared with Raney Ni. After 130 h’ on stream aqueous-phase reforming of glycerol, the amorphous Ni-B catalyst was transformed to hexagonal closed-packed (hcp) Ni crystallites. The high selectivity towards hydrogen and catalytic stability may be due to the formation of hcp Ni crystallites during reaction and the protection of B2O3. The AP Ni catalyst was found to be 35–50% more active in terms of the H2 production rate and 17–31% more selective toward H2 as compared to Raney Ni. The reforming reaction at different reaction temperature, feedstock concentration, feedstock flow rate and other biomass derivatives i.e., ethylene glycol and sorbitol, were also investigated over AP Ni catalyst.A Ni-B amorphous alloy catalyst (AP Ni) with higher stability and selectivity towards H2 was developed for an APR process of biomass derivatives.Highlights► A Ni-B amorphous alloy catalyst was used in aqueous-phase reforming of glycerol. ► High stability and high selectivity to H2 was obtained on Ni-B alloy catalyst. ► After long term APR of glycerol, Ni-B catalyst was transformed to hcp Ni. ► The good performance of Ni-B catalyst may be due to the formation of hcp Ni. ► The Ni-B catalyst can be used in the APR of ethylene glycol and sorbitol.
Co-reporter:Anmiao Wang, Jiawen Ren, Bianfang Shi, Guanzhong Lu, Yanqin Wang
Microporous and Mesoporous Materials 2012 Volume 151() pp:287-292
Publication Date(Web):15 March 2012
DOI:10.1016/j.micromeso.2011.10.022
Mesoporous carbon materials with partially graphitized structure were synthesized by a one-pot, co-assembly of tri-block copolymer with phenolic resin under the assistance of ammonium ferric citrate. The structure was characterized by XRD, TEM, N2 sorption and TG/DTA. The mesoporous structure of the polymer conserved after the addition of ammonium ferric citrate. The graphitization of carbon material was achieved at lower temperature (700 °C), which was attributed to the catalytic property of iron, as well as the formation of carbon-polymer structure pre-carbonized at 350 °C. The final graphitic porous carbon materials had high surface area and performed well in the selective oxidation of benzyl alcohol to benzaldehyde. The selectivity to benzaldehyde reached 96.2%.Graphical abstractHighlights► Partially graphitized mesoporous carbon was obtained by one-pot synthesis. ► The carbonization temperature was as lower as 700 °C. ► The low temperature carbonization is attributed to the catalytic property of iron. ► The graphitic porous carbon has excellent activity in oxidation of benzyl alcohol.
Co-reporter:Bianfang Shi, Jiawen Ren, Xiaohui Liu, Guanzhong Lu, Yanqin Wang
Synthetic Metals 2012 Volume 162(15–16) pp:1443-1450
Publication Date(Web):September 2012
DOI:10.1016/j.synthmet.2012.06.015
Well-defined superparamagnetic Fe3O4/SiO2/polyaniline (PANi) core–shell–shell microspheres with smooth surface are synthesized as the first time. Fe3O4/SiO2 core–shell microspheres modified by poly(vinylpyrrolidone) (PVP) are coated with PANi through in situ polymerization of aniline monomers in ethanol dispersion. Low polymerization temperature is a key factor for coating PANi on the surface of silica. Rattle-type Fe3O4@PANi hollow microspheres are obtained and the outermost rigid PANi layer could be kept with the hollow structure after etching spacer silica layers by NaOH. The thickness of PANi layer could be controlled by adjusting the concentration of aniline. The cavity size of rattle-type Fe3O4@PANi hollow microspheres is related to the thickness of spacer silica layer. As a potential carrier for catalysts, gold nanoparticles are loaded in cavities of the rattle-type Fe3O4@PANi hollow microspheres.Highlights► Polyaniline is coated on the surface of Fe3O4/SiO2 core–shell microspheres. ► The rattle-type Fe3O4@polyaniline hollow microspheres with big cavity are obtained after etching the middle layer silica. ► The low temperature is a key factor for coating polyaniline on the surface of silica. ► The gold nanoparticles are successfully loaded inside the cavities of the rattle-type Fe3O4@PANi hollow microspheres.
Co-reporter:Li Wan, Lingyi Zhang, Wen Lei, Yaxian Zhu, Weibing Zhang, Yanqin Wang
Talanta 2012 Volume 98() pp:277-281
Publication Date(Web):30 August 2012
DOI:10.1016/j.talanta.2012.07.002
The rod-shaped SBA–15–C18 mesoporous nanoparticles were incorporated into hybrid organic–inorganic monolithic column with aminopropyl moiety to develop novel stationary phases with mixing mechanism of reverse phase and ion exchange. Experimental conditions including dispersion pattern, nanoparticles percentage were optimized for simple and stable column preparation. The monolithic columns were evaluated with mixture of organic acids in capillary electrochromatography (CEC) mode and the column efficiency reaches 280, 000 plates/m. The results indicate that the column containing nanoparticles enhances both selectivity and column efficiency due to high specific surface area of nanoparticles and mixing separation mechanism.Highlights► A novel monolithic stationary phase combining nanoparticles was developed. ► The surface area of monolith is significantly increased by adding nanoparticles. ► Incorporation of nanoparticles enhances both selectivity and column efficiency. ► The mechanism is mixed mode of reverse phase and ion exchange.
Co-reporter:Muhammad Usman Azmat;Yong Guo;Yun Guo;Guanzhong Lu
Journal of Porous Materials 2012 Volume 19( Issue 5) pp:605-613
Publication Date(Web):2012 October
DOI:10.1007/s10934-011-9511-8
Cinchona functionalized mesoporous silica is synthesized by one pot synthesis method. The main silica precursor (TEOS) is co-condensed with a cinchonidine molecule linked organosilane which is renovated by triethoxy silane moiety at its C11 position to yield cinchona functionalized silica. The subsequent deposition of Pt nanoparticles over functionalized silica provides a catalytic system for the enantioselective hydrogenation of α-activated ketone (Orito’s reaction). Thus-developed catalyst system is found to be enantioselective with an enantiomeric excess (e.e) of 35.6%.
Co-reporter:Jianjian Wang, Wenjie Xu, Jiawen Ren, Xiaohui Liu, Guanzhong Lu and Yanqin Wang
Green Chemistry 2011 vol. 13(Issue 10) pp:2678-2681
Publication Date(Web):09 Aug 2011
DOI:10.1039/C1GC15306D
A novel carbon-based solid acid, which was prepared by a facile and eco-friendly approach from glucose and p-toluenesulfonic acid (TsOH), was used to catalyze fructose dehydration into 5-hydroxymethylfurfural (HMF) for the first time and exhibits excellent catalytic performance. As high as 91.2% yield of HMF was achieved in dimethyl sulfoxide (DMSO) at 130 °C after only 1.5 h. Besides, this catalyst also displayed a good reusability.
Co-reporter:Xin Gu, Tianlong Jiang, Haixiang Tao, Shutian Zhou, Xiaohui Liu, Jiawen Ren, Yanqin Wang, Guanzhong Lu and Wolfgang Schmidt
Journal of Materials Chemistry A 2011 vol. 21(Issue 3) pp:880-886
Publication Date(Web):12 Nov 2010
DOI:10.1039/C0JM01973A
Hydrothermally highly stable mesoporous aluminosilicate spheres with radial channels were synthesized in the CTAB–NaF–TPAOH system through a one-step procedure at high aging temperature. The characterization by transmission electron microscopy (TEM), X-ray diffraction (XRD), nitrogen adsorption/desorption analysis, 27Al MAS solid state NMR spectroscopy, pyridine adsorption FT-IR combined with the typical hydrothermal treatments showed that this kind of material exhibited large surface area, specific pore arrangement, strong acidity and high hydrothermal stability. Detailed studies suggest that F− ions direct the perpendicular arrangement of aluminosilicate clusters during the hydrothermal treatment at 160 °C, while TPA+ stabilized the structure. Both F− and TPA+ ions are considered to improve the acidity and hydrothermal stability of this material through coordination of framework atoms, thus, enhancing the condensation of Si–O–Si bonds in the amorphous pore walls. Due to the accessible radial pore arrangement and high acidity, the catalytic activity for Friedel–Crafts alkylation of toluene with benzyl alcohol was excellent with 100% conversion of benzyl alcohol.
Co-reporter:Weimo Zhu, Lei Wang, Rui Zhao, Jiawen Ren, Guanzhong Lu and Yanqin Wang
Nanoscale 2011 vol. 3(Issue 7) pp:2862-2864
Publication Date(Web):01 Jun 2011
DOI:10.1039/C1NR10274E
The electromagnetic and microwave absorbing properties of nickel ferrite nanocrystals were investigated for the first time. There were two frequencies corresponding to the maximum reflection loss in a wide thickness range from 3.0 to 5.0 mm, which may be bought by the nanosize effect and the good crystallization of the nanocrystals.
Co-reporter:Wenjie Xu, Haifeng Wang, Xiaohui Liu, Jiawen Ren, Yanqin Wang and Guanzhong Lu
Chemical Communications 2011 vol. 47(Issue 13) pp:3924-3926
Publication Date(Web):23 Feb 2011
DOI:10.1039/C0CC05775D
A new strategy was developed for the direct conversion of furfural to 1,5-pentanediol by the hydrogenolysis of the furan ring under mild conditions based on Pt/Co2AlO4 catalyst. This is the first report of the direct catalytic conversion of furfural to 1,5-pentanediol with high yield.
Co-reporter:Xin Gu, Weimo Zhu, Chunjiang Jia, Rui Zhao, Wolfgang Schmidt and Yanqin Wang
Chemical Communications 2011 vol. 47(Issue 18) pp:5337-5339
Publication Date(Web):28 Mar 2011
DOI:10.1039/C0CC05800A
Highly ordered mesoporous NiFe2O4 with excellent microwave absorption properties has been synthesized by using mesoporous silica (KIT-6) as a hard template.
Co-reporter:Weili Zhang, Haixiang Tao, Baohua Zhang, Jiawen Ren, Guanzhong Lu, Yanqin Wang
Carbon 2011 Volume 49(Issue 6) pp:1811-1820
Publication Date(Web):May 2011
DOI:10.1016/j.carbon.2010.12.050
The carbonaceous monoliths rich in surface sulfonic acid groups were synthesized by one-pot hydrothermal carbonization of the mixture of p-toluenesulfonic acid/glucose/resorcinol at 180 °C. The Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy characterizations confirmed the presence of surface sulfonic groups on these monoliths. The catalytic performance of this kind of carbonaceous material as a solid-acid catalyst was studied in the reaction of acetalization of benzaldehyde and the results showed that it has high activity and reusability. Then, these monoliths were further carbonized and activated to form monolithic carbons with high surface area and large pore volume. The surface area and pore volume per mass increased with prolonging the activation time (0–6 h) and the best results on 6-h activated samples were 2337 m2/g and 2.12 cm3/g. Due to the decrease in bulk density the volumetric surface area increased initially until maximum and then slightly dropped down during the activation. These carbonized and activated samples showed better oxidation resistance than one commercial activated carbon under air. Moreover, the adsorption capacity for dye molecules with different size on these activated samples was significant higher than that on commercial activated carbons and a synthetic ordered mesoporous carbon.
Co-reporter:Weimo Zhu, Jiawen Ren, Xin Gu, Muhammad Usman Azmat, Guanzhong Lu, Yanqin Wang
Carbon 2011 Volume 49(Issue 4) pp:1462-1472
Publication Date(Web):April 2011
DOI:10.1016/j.carbon.2010.12.016
Hermetically-sealed graphite encapsulated cobalt core/shell nanostructures have been prepared by the CO Boudouard reaction using in situ generated cobalt as the catalyst. Only core/shell nanostructures were obtained, rather than a mixture of cobalt nanoparticles with carbon nanotubes or nanofibers. The magnetic cobalt nanoparticles are highly crystallized with a hexagonal-close packed crystal phase (average diameter of ca. 25 nm) and coated with an 8–9 nm thick graphitic shell. The nanostructures have a high saturation magnetization of 85 emu/g and can be easily separated by an external magnet. The creation of the hermetically-sealed graphitic shell not only keeps the magnetic cobalt nanoparticles from reacting with strong mineral acids, but also has biocompatibility and makes further functionalization easy. A pseudo-planar aromatic molecule, xylenol orange, was used as the model molecule because it can be absorbed on the graphitic shell mainly by π–π stacking interaction. This was confirmed by Raman and ultraviolet–visible spectroscopy. Graphite encapsulated Fe2Co and Fe0.64Ni0.36 alloy core/shell nanostructures were also fabricated by this method.
Co-reporter:Tianlong Jiang, Haixiang Tao, Jiawen Ren, Xiaohui Liu, Yanqin Wang, Guanzhong Lu
Microporous and Mesoporous Materials 2011 Volume 142(Issue 1) pp:341-346
Publication Date(Web):June 2011
DOI:10.1016/j.micromeso.2010.12.020
In this paper, extremely hydrothermal stable mesoporous Al-SBA-15 with controllable Al content has been synthesized by using triblock copolymer (P123) as template under an assistance of NaF at 160 °C. This kind of material was characterized by powder X-ray diffraction (XRD), N2 sorption isotherms, transmission electron microscopy (TEM), 27Al MAS NMR, energy-dispersive X-ray spectroscopy (EDX), and ammonia-temperature programmed desorption (NH3-TPD). It was found that nearly all Al added into the initial reaction mixture can be introduced into the product and thus-synthesized Al-SBA-15 maintained the well-ordered mesostructure and high surface area, large pore size, thick pore wall and high pore volume even after being hydrothermally treated at 100 °C for 300 h or steamed at 600 °C for 6 h. This kind of Al-SBA-15 is an efficient catalyst for the protection of carbonyl compound reactions under mild conditions.Research highlights► Extremely hydrothermal stable mesoporous Al-SBA-15 was synthesized. ► NaF was used as an assistant, which improved the hydrothermal stability. ► The reduction of BET surface area was very low after hydrothermally treatment. ► This kind of Al-SBA-15 was an efficient catalyst and had good reusability.
Co-reporter:Wenjie Xu, Xiaohui Liu, Jiawen Ren, Huihui Liu, Yichun Ma, Yanqin Wang, Guanzhong Lu
Microporous and Mesoporous Materials 2011 Volume 142(Issue 1) pp:251-257
Publication Date(Web):June 2011
DOI:10.1016/j.micromeso.2010.12.008
A novel mesoporous Co–Al spinel catalyst with high surface area and suitable basicity was prepared by the thermal decomposition of Co–Al hydrotalcite-like compound. The properties of the solid base catalyst were characterized by XRD, FTIR, TEM, nitrogen sorption and CO2-TPD. The formation mechanism of the mesopores and the Co–Al spinel structure was also investigated by TG/DTA and mass-spectrometer, respectively. This is due to the partial oxidation of Co2+ ions and the dehydration of the interface OH groups in precursor. The formed Co3+ ions collapsed into the interlayer space, coordinated with the adjacent oxygen atoms (tetrahedral or octahedral), worked as pillars between layers and made the interlayer space to be almost opened (mesopores formed). The partial oxidation of Co2+ ions plays a critical role in the phase transformation and the formation of mesopores. The as-obtained mesoporous Co–Al spinel-type solid base catalyst was first used in the aldol condensation of furfural with acetone and the self-condensation of acetone and found that it had good activity and excellent selectivity in both reactions. The stability studies showed that the catalyst can be completely regenerated easily by calcination.Graphical abstractA novel mesoporous Co–Al spinel type solid base catalyst with high surface area was prepared, which was used for the aldol condensation of furfural with acetone and the self-condensation of acetone with high activity and easy regeneration.Research highlights► A novel mesoporous Co–Al spinel-type solid base catalyst was prepared. ► The partial oxidation of Co2+ and dehydration of interface OH play the role. ► This kind of solid base catalyst was used in Aldol condensation with good activity. ► The catalytic activity can be completely regenerated easily by calcination.
Co-reporter:Haixiang Tao, Changlin Li, Jiawen Ren, Yanqin Wang, Guanzhong Lu
Journal of Solid State Chemistry 2011 Volume 184(Issue 7) pp:1820-1827
Publication Date(Web):July 2011
DOI:10.1016/j.jssc.2011.05.023
Mesoporous zeolite (silicalite-1, ZSM-5, TS-1) single crystals have been successfully synthesized by adding soluble starch or sodium carboxymethyl cellulose (CMC) to a conventional zeolite synthesis system. The obtained samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen sorption analysis, 27Al magic angle spinning nuclear magnetic resonance (27Al MAS NMR), temperature-programmed desorption of ammonia (NH3-TPD) and ultraviolet–visible spectroscopy (UV–vis). The SEM images clearly show that all zeolite crystals possess the similar morphology with particle size of about 300 nm, the TEM images reveal that irregular intracrystal pores are randomly distributed in the whole crystal. 27Al MAS NMR spectra indicate that nearly all of the Al atoms are in tetrahedral co-ordination in ZSM-5, UV–vis spectra confirm that nearly all of titanium atoms are incorporated into the framework of TS-1. The catalytic activity of meso-ZSM-5 in acetalization of cyclohexanone and meso-TS-1 in hydroxylation of phenol was also studied. The synthesis method reported in this paper is cost-effective and environmental friendly, can be easily expended to prepare other hierarchical structured zeolites.Graphical abstractMesoporous zeolite single crystals were synthesized by using cheap porogens as template.Highlights► Mesoporous zeolite (silicalite-1, ZSM-5, TS-1) single crystals were synthesized. ► Soluble starch or sodium carboxymethyl cellulose (CMC) was used as porogens. ► The mesoporous zeolites had connected mesopores although closed pores existed. ► Higher catalytic activities were obtained.
Co-reporter:Lei Wang, Jiawen Ren, Xiaohui Liu, Guanzhong Lu, Yanqin Wang
Materials Chemistry and Physics 2011 Volume 127(1–2) pp:114-119
Publication Date(Web):16 May 2011
DOI:10.1016/j.matchemphys.2011.01.043
Three-dimensional nanoflowers consisting of uniform crystalline SnO2 nanorods were spontaneously grown by the gradual hydrolysis of SnS32− in an aqueous system at 180 °C. The resulting material was characterized by using SEM, TEM, EDX, SAED, XRD, and UV–vis techniques. The results clearly show that these uniform crystalline SnO2 nanorods grow in the [0 0 1] direction with the enclosing facets of {1 1 0}. It is believed that the controlled release of Sn(OH)62− is achieved via the gradual hydrolysis of SnS32−, which is accounting for the oriented growth. The band gap energy (Eg) of the SnO2 nanoflowers deduced from the diffused UV–vis spectrum is 3.60 eV and the photoluminescence spectra of the nanoflowers shows three emission peaks centered at wavelengths of 355, 390 and 465 nm, respectively.Research highlights► Na2SnS3 is first used as the tin source for the formation of SnO2 nanoflowers. ► SnO2 nanoflowers were composed of nanorods. ► The controlled release of Sn(OH)62− results in the oriented growth along c-axis. ► The PL peak at 390 nm is weak until the excitation wavelength increases to 335 nm.
Co-reporter:Xiaohuin Liu;Yong Guo;Wenjie Xu;Yanqin Wang;Xueqing Gong
Kinetics and Catalysis 2011 Volume 52( Issue 6) pp:817-822
Publication Date(Web):2011 December
DOI:10.1134/S0023158411060115
The influence of the alumina support on the catalytic activity of Pt/Al2O3 catalysts in aqueous phase reforming of ethylene glycol to hydrogen was studied. The catalysts were prepared by impregnation of γ-, δ-, and α-alumina with H2PtCl6. The highest rate of hydrogen production (452 μmol min−1 g−1) obtained with the Pt/α-Al2O3 catalyst can be related to the highest extent of dispersion of Pt on α-Al2O3. XPS, TEM-EDX and TPR-H2 measurements showed the absence of chloride-containing surface complexes in the Pt/α-Al2O3 catalyst. However, chloride-containing entities were found on the surface of Pt/γ-Al2O3 and Pr/δ-Al2O3 catalysts. When chloride ions are removed chlorinated Pt species facilitate the sintering of Pt crystallites and in this way affect the extent of Pt dispersion. Moreover, depending upon the particular crystalline form, alumina atoms have different coordination and alumina surfaces contain varying amounts of OH groups of different nature which affect the interaction between Pt and the support.
Co-reporter:Wenjie Xu;Qineng Xia;Yu Zhang;Yong Guo; Yanqin Wang; Guanzhong Lu
ChemSusChem 2011 Volume 4( Issue 12) pp:1758-1761
Publication Date(Web):
DOI:10.1002/cssc.201100361
Co-reporter:Shengpu Ma;Yanqin Wang;Yingchun Zhu
Journal of Porous Materials 2011 Volume 18( Issue 2) pp:233-239
Publication Date(Web):2011 April
DOI:10.1007/s10934-010-9375-3
Mesoporous silica nanoparticles (MSN) have been synthesized at room temperature under assistance of n-hexane by using tetraethyl orthosilicate (TEOS) as a silica source and cetyltrimethylammonium bromide (CTAB) as a structure directing agent. Powder X-ray diffraction studies showed that the quantity of n-hexane added into the solution was critical for the ordering of the final mesostructures. The particle size of MSN was between 200 and 400 nm, which is suitable for endocytosis by human cells. The drug loading capability of MSN prepared through this route was measured and the influence of the pulsed pressure drop on drug delivery was studied. This study showed that the delivery rate of ibuprofen in a simulated body fluid solution increased dramatically under the pulsed pressure drop.
Co-reporter:Baohua Zhang;Jiawen Ren;Xin Gu;Xiaohui Liu;Changlin Li
Journal of Porous Materials 2011 Volume 18( Issue 6) pp:743-750
Publication Date(Web):2011 December
DOI:10.1007/s10934-010-9436-7
Activated carbon-based carbon/carbonaceous composites with different surface functional groups were synthesized by a hydrothermal carbonization-deposition method in which commercial activated carbon was exposed to a gaseous mixture of furfural/water or furfural/acrylic acid/water at 180 °C to form the carbon/carbonaceous composites. The products were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, and nitrogen sorption analysis. The results indicate that the surface area and pore volume of the composite can be tailored by tuning the hydrothermal treatment time. More importantly, different functional groups can be anchored onto the composite, and composites with surface hydroxyl or carboxylic or amine groups were prepared.
Co-reporter:Muhammad Usman Azmat, Yong Guo, Yun Guo, Yanqin Wang, Guanzhong Lu
Journal of Molecular Catalysis A: Chemical 2011 Volume 336(1–2) pp:42-50
Publication Date(Web):14 February 2011
DOI:10.1016/j.molcata.2010.12.008
A single unit catalyst system (Pt/silica–chiral modifier) is developed for the enantioselective hydrogenation of ethyl pyruvate. Cinchonidine was tethered directly without prior modification over carboxylate functionalized SBA-15 by the reaction of vinyl group in cinchonidine with –COOH group in functionalized SBA-15 through ester linkage. Then Pt nanoparticles were deposited over cinchonidine tethered SBA-15. The mesostructures were characterized by small-angle XRD, N2 sorption and TEM, while the surface functionalization was confirmed by FTIR, TG/DTA and solid state 13C NMR. Enantioselectivity of the catalyst system for hydrogenation of ethyl pyruvate was determined by GC/FID. The highest enantiomeric excess was achieved as 70.8% and the catalyst recyclability was authenticated even after 3rd reuse without significant loss in enantiomeric excess.Graphical abstractA single unit heterogeneous Chiral catalyst system (Pt/CA-SBA-CD) is prepared for the enantioselective hydrogenation of ethyl pyruvate. Cinchonidine is tethered successfully with carboxylate functionalized SBA-15 which is further impregnated by Pt nanoparticles. The highest enantiomeric excess was achieved as 70.8% with adequate recyclability.Research highlights▶ A unique heterogeneous chiral catalyst is developed for hydrogenation. ▶ Cinchonidine is directly tethered with CA-SBA-15. ▶ Pt nanoparticles deposit in the channels of cinchonidine-tethered CA-SBA-15. ▶ Catalyst system provides a maximum of 70.8% e.e. value with adequate recyclability.
Co-reporter:Yangang Wang, Fengyuan Zhang, Yong Guo, Yanqin Wang, Jiawen Ren, Dongsheng Qiao, Xiaohui Liu, Guanzhong Lu
Materials Chemistry and Physics 2010 Volume 120(Issue 1) pp:23-30
Publication Date(Web):15 March 2010
DOI:10.1016/j.matchemphys.2009.10.015
In this work, novel three-dimensional (3D) navicular ceria micro/nanocomposite architecture with multi-layered structure was synthesized for the first time via solution reaction followed by a simple hydrothermal treatment in the presence of lysozyme. During the synthesis procedure, a 3D navicular ceria precursor (Ce2O(CO3)2·H2O) with multi-layered structure was obtained after hydrothermal treatment at 100 °C for 10 h. Ceria with the same morphology can be obtained after thermal decomposition of this Ce2O(CO3)2·H2O precursor. Structural properties of the products were characterized by XRD, TG-DTA, FT-IR, SEM, TEM, and N2-sorption techniques. Then a possible layer-by-layer electrostatic self-assembled growth mechanism was proposed for the formation of this 3D navicular architecture based on the experimental results and detail analysis of the evolution process of ceria precursors. Furthermore, a mold reaction of the catalytic oxidation of CO was conducted on the as-obtained CeO2 and gold supported catalyst, both showed excellent activity and durability for CO conversion.
Co-reporter:Yangang Wang, Yanqin Wang, Jiawen Ren, Yan Mi, Fengyuan Zhang, Changlin Li, Xiaohui Liu, Yun Guo, Yanglong Guo, Guanzhong Lu
Journal of Solid State Chemistry 2010 Volume 183(Issue 2) pp:277-284
Publication Date(Web):February 2010
DOI:10.1016/j.jssc.2009.11.009
Recently, extensive works have been devoted to the morphology control of mesoporous materials with respect to their use in various applications. In this paper, we used two kinds of mesoporous silica, SBA-15 rods and spheres as hard templates to synthesize morphology-controllable mesoporous metal oxides. By carefully controlling the loading of metal precursors in the mesopores of the hard template, mesoporous Co3O4 and CeO2 with different morphologies, such as micrometer-sized rod, hollow sphere, saucer-like sphere, and solid sphere were conveniently obtained. The structural properties of these materials were characterized by XRD, BET, SEM and TEM. In addition, it is found that the differences observed in the textural properties of the two mesoporous metal oxides nanocasted from the same template can be attributed to the properties of metal precursors and the interaction between metal oxide and SiO2. Thus-obtained mesoporous metal oxides with such special morphologies may have a potential application in the field of environmental catalytic oxidation.Mesoporous Co3O4 and CeO2 with different morphologies, such as micrometer-sized rod, hollow sphere, saucer-like sphere, and solid sphere were synthesized by nanocasting.
Co-reporter:Yi Liu, Cun Wen, Yun Guo, Guanzhong Lu, Yanqin Wang
Journal of Molecular Catalysis A: Chemical 2010 316(1–2) pp: 59-64
Publication Date(Web):
DOI:10.1016/j.molcata.2009.09.022
Co-reporter:Yi Liu;Cun Wen;Yun Guo ;Xiaohui Liu;Jiawen Ren Dr.;Guanzhong Lu ;Yanqin Wang
ChemCatChem 2010 Volume 2( Issue 3) pp:336-341
Publication Date(Web):
DOI:10.1002/cctc.200900246
Abstract
CO disproportionation produces carbon deposits that cover active sites and induce catalyst deactivation. However, understanding of this detrimental reaction on reduced ceria is deficient. Herein, the reversibility and reaction mechanism of CO disproportionation on reduced ceria are investigated. The reversibility of the CO disproportionation was studied by CO pulse, isotopic oxygen tracer, thermal analysis, and CO2 pulse experiments. In situ diffuse-reflectance infrared Fourier transform spectra indicate that the CO bond of the CO molecule on Ce3+ ion is weakened. With CO bond dissociation, asymmetrical inorganic carboxylate species are formed. These species are the key reaction intermediates in CO disproportionation and are further converted to produce CO2. EPR experiments indicate that the unpaired electrons produced by the reduction weaken the CO bond through back-donation of electrons.
Co-reporter:Yi Liu, Cun Wen, Yun Guo, Guanzhong Lu and Yanqin Wang
The Journal of Physical Chemistry C 2010 Volume 114(Issue 21) pp:9889-9897
Publication Date(Web):May 10, 2010
DOI:10.1021/jp101939v
Many properties of dopants have been investigated to explore the key factor that influenced the CO oxidation activity of M-doped ceria (CeM). Nevertheless, these reports were controversial. Herein, the Pauling electronegativity (χP) of the M was presented as a convenient guide to screen a proper dopant for ceria. Kinetics results indicated that the T10 (the temperature when CO conversion reached 10%) of CeM73 catalysts (Ce/M molar ratio was 7/3; M = Cu, Ti, Zr, and Tb) was linearly dependent on the χP of the M, which could adjust the amount of active lattice oxygen (AOL). The AOL was important to catalyst activity because lattice oxygen extraction was the rate-determining step in the overall reaction.
Co-reporter:Changlin Li, Yanqin Wang, Bianfang Shi, Jiawen Ren, Xiaohui Liu, Yangang Wang, Yun Guo, Yanglong Guo, Guanzhong Lu
Microporous and Mesoporous Materials 2009 Volume 117(1–2) pp:104-110
Publication Date(Web):1 January 2009
DOI:10.1016/j.micromeso.2008.06.017
MFI nanozeolite microspheres with intercrystal mesopores were synthesized by a steam-assisted crystallization–aggregation method, starting with close packed amorphous SiO2 or Al-containing SiO2 colloidal nanoparticles. The obtained samples with different Si/Al ratios were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM)/ transmission electron microscopy (TEM) observations, nitrogen adsorption analyses and 27Al magic angle spinning nuclear magnetic resonance (NMR). The SEM images clearly showed that the mean size of nanozeolite microspheres was ca. 0.5–3 μm, agglomerated from zeolite nanocrystals and varied with different Si/Al ratios. N2 sorption analyses as well as TEM micrographs indicated the dual-porosity of samples, one is from intracrystal micropores, and the other is from intercrystal mesopores. 27Al MAS-NMR suggested nearly all of the Al atoms were located at tetrahedral-coordinated sites in the framework. Furthermore, nanozeolite microspheres with various Si/Al ratios, even Si/Al equal to five, could be prepared by this facile route and less structure-directing agent was needed compared to conventional approach. This simple method could be easily extended to prepare other hierarchically structured zeolites.
Co-reporter:Yangang Wang, Fengyuan Zhang, Yanqin Wang, Jiawen Ren, Changlin Li, Xiaohui Liu, Yun Guo, Yanglong Guo, Guangzhong Lu
Materials Chemistry and Physics 2009 Volume 115(2–3) pp:649-655
Publication Date(Web):15 June 2009
DOI:10.1016/j.matchemphys.2009.01.027
Monodispersed SBA-15 rods with different lengths (from hexagonal platelets to short rods, and to longer rods) have been synthesized by using triblock copolymer P123 as a structure-directing agent and glycerol as a cosolvent. Our studies showed that glycerol is indispensable for tuning the length of SBA-15 rods. And, in the presence of glycerol, the length of these SBA-15 rods was reversely proportional to the concentration of the acid (HCl) in the synthetic mixture. Based on our characterizations (XRD, SEM, TEM, N2-sorption, and dynamic light scattering (DLS) analyses) and the literature results, a possible glycerol-induced growth mechanism was proposed for the formation of these SBA-15 rods. Furthermore, an adsorption of lysozyme on these SBA-15 materials was investigated and the results showed that they all exhibited rapid lysozyme immobilization and high adsorption capacity (the highest up to 907 mg g−1 for capsulelike SBA-15 synthesized at MHCl = 2.0 M).
Co-reporter:Xin Gu, Changlin Li, Xiaohui Liu, Jiawen Ren, Yanqin Wang, Yanglong Guo, Yun Guo and Guanzhong Lu
The Journal of Physical Chemistry C 2009 Volume 113(Issue 16) pp:6472-6479
Publication Date(Web):2017-2-22
DOI:10.1021/jp810749s
Nanosized multilayered silica vesicles have been synthesized through a dual-template way by using cetyltrimethylammonium bromide (CTAB) and C3F7O(CFCF3CF2O)2CFCF3 CONH(CH2)3N+(C2H5)2CH3I− (FC-4) as the cotemplates and tetraethyl orthosilicate (TEOS) as the siliceous precursor. According to transmission electron microscopy, X-ray diffraction, and N2 sorption analysis, the formation of the multilayered silica vesicles passed through the route of the normal mesoporous silica spheres (MCM-41) to irregular hexagonal structures with cavities inside MCM-41 spheres and finally to the small-sized multilayered siliceous vesicles with the increase of FC-4/CTAB molar ratio. The possible mechanism of the two kinds of micelles cooperation was discussed. The synthesized silica vesicle spheres were 30−40 nm with a few shells that may facilitate the transport of the molecules. Furthermore, the vesicular structure was also obtained by aging at 150 °C, which maintained high surface area even after hydrothermal treatment in boiling water for 48 h. The higher hydrothermal stability, high surface area, and pore volume would benefit the loading of catalysts and increase the adsorption capacity.
Co-reporter:Yangang Wang, Jiawen Ren, Xiaohui Liu, Yanqin Wang, Yun Guo, Yanglong Guo, Guanzhong Lu
Journal of Colloid and Interface Science 2008 Volume 326(Issue 1) pp:158-165
Publication Date(Web):1 October 2008
DOI:10.1016/j.jcis.2008.07.012
Co-reporter:Yangang Wang, Xiaohong Yuan, Xiaohui Liu, Jiawen Ren, Weiyi Tong, Yanqin Wang, Guanzhong Lu
Solid State Sciences 2008 Volume 10(Issue 9) pp:1117-1123
Publication Date(Web):September 2008
DOI:10.1016/j.solidstatesciences.2007.11.018
In this paper, a series of ordered mesoporous single-crystal Cr2O3 samples were synthesized through a hard-templating pathway by using three-dimensional (3D) cubic mesoporous silica, KIT-6, as the template and chromium nitrate as the precursor. In the synthesis, the intermediate composites (chromium nitrate/KIT-6) were calcined in air for 4 h at different temperatures (from 400 to 700 °C, interval 100 °C) to decompose the nitrate species. Then, the silica template was removed by dissolution in 10% HF solution twice. The resulting Cr2O3 samples were characterized by XRD, TEM, XPS, and N2-sorption analysis and their catalytic properties were also investigated in the oxidation of toluene. These results showed that the obtained ordered mesoporous Cr2O3 are exact reverse-replica of the template. It was also found that the catalytic activity was related to mesostructure and/or surface area as well as the calcination temperatures.A series of ordered mesoporous single-crystal Cr2O3 catalysts for the toluene oxidation were prepared through a hard-templating pathway and characterized by XRD, TEM, XPS, and N2-sorption analysis. These results showed that the obtained ordered mesoporous Cr2O3 are exact reverse-replica of the template and their catalytic activity was related to mesostructure and/or surface area as well as the calcination temperatures.
Co-reporter:Yangang Wang ; Jiawen Ren ; Yanqin Wang ; Fengyuan Zhang ; Xiaohui Liu ; Yun Guo ;Guanzhong Lu
The Journal of Physical Chemistry C 2008 Volume 112(Issue 39) pp:15293-15298
Publication Date(Web):September 9, 2008
DOI:10.1021/jp8048394
Ordered mesoporous LaCoO3 perovskite with high surface area was synthesized via nanocasting strategy by using ordered mesoporous cubic (Ia3d) vinyl silica as the template. The sample, prepared by filling mesopores in silica template with a La−Co citrate complex precursor followed by calcination and silica removal, was characterized by XRD, TEM, and nitrogen sorption techniques, and its catalytic activity was tested for complete methane oxidation. The wide-angle XRD pattern showed LaCoO3 perovskite was formed and no La-oxide/Co-oxide phases were detected in the obtained material. This LaCoO3 perovskite displayed a high BET surface area of 96.7 m2 g−1 from nitrogen sorption analysis and a three-dimensional ordered mesostructure from TEM images, as well as a small-angle XRD pattern. Moreover, this material showed much higher activity in the complete methane oxidation than the conventional bulk LaCoO3 perovskite. The light-off temperature (T10) and the half-conversion temperature (T50) were at 335 and 470 °C, respectively. Further analysis by means of H2-TPR and XPS techniques showed that the existence of high valent cobalt ions and high content of O22−/O− species contributed to the high activity.
Co-reporter:Yaojun Wang, Xiaohui Liu, Rui Zhao, Yanqin Wang, Yanglong Guo, Yun Guo, Zhigang Zhang, Yunsong Wang, Guanzhong Lu
Microporous and Mesoporous Materials 2007 Volume 102(1–3) pp:325-332
Publication Date(Web):4 May 2007
DOI:10.1016/j.micromeso.2006.12.047
In this paper, different organic group-functionalized mesoporous ethanesilicas have been synthesized by the co-condensation of 1,2-bis-(triethoxysilyl) ethane (BTEE) and organosilanes under basic conditions, using cetyltrimethylammonium bromide (CTAB) as a template. High quality mesoporous materials were obtained with MCM-41-type structure. But the employing of different organic groups, such as vinyl, aminopropyl, glycidoxypropyl, mercaptopropyl, leads to different morphologies. The ratio of organosilane to BTEE also affects the mesostructures and morphologies of the final materials. Using the similar method, Ce-doped mesoporous ethanesilica was also obtained.
Co-reporter:Jinxu Xi, Qineng Xia, Yi Shao, Daqian Ding, Panpan Yang, Xiaohui Liu, Guanzhong Lu, Yanqin Wang
Applied Catalysis B: Environmental (February 2016) Volume 181() pp:699-706
Publication Date(Web):February 2016
DOI:10.1016/j.apcatb.2015.08.052
Co-reporter:Bianfang Shi, Yanqin Wang, Jiawen Ren, Xiaohui Liu, Ye Zhang, Yanglong Guo, Yun Guo, Guanzhong Lu
Journal of Molecular Catalysis B: Enzymatic (April 2010) Volume 63(Issues 1–2) pp:50-56
Publication Date(Web):1 April 2010
DOI:10.1016/j.molcatb.2009.12.003
The superparamagnetic Fe3O4 microspheres about 300 nm diameter were prepared by the solvothermal method. After treated with chlorohydric acid, it was coated with aminopropyl-functionalized amorphous silica by the condensation of tetraethylorthosilicate (TEOS) and γ-aminopropyltriethoxysilane (APTES) through Stöber modified method. FT-IR, elemental analysis and TEM were used to characterize the aminopropyl-functionalized silica-coated magnetic microspheres, and then they were first used as magnetic separation carriers for immobilization of penicillin G acylase (PGA). The results showed that the amino content of the carriers has a little influence on the apparent initial activity, while the immobilization method and the shell thickness have more obvious influence on the apparent initial activity. The immobilized PGA (IMPGA) obtained through covalent attachment almost has no leaching and can retain above 78% of activity after 10 consecutive operations and exhibits higher resistance to thermal stability. More interesting, the silica-coated magnetic microspheres show high saturation magnetization and the obtained IMPGA can be separated quickly using an external magnetic field.
Co-reporter:Panpan Yang, Qiqi Cui, Yanhong Zu, Xiaohui Liu, Guanzhong Lu, Yanqin Wang
Catalysis Communications (5 June 2015) Volume 66() pp:55-59
Publication Date(Web):5 June 2015
DOI:10.1016/j.catcom.2015.02.014
•A non-precious metal catalyst Ni/Co3O4 was prepared using a simple hydrothermal method.•As high as 76% DMF yield was achieved under relatively mild conditions.•The catalyst can be recycled for 6 times without a significant loss of activity.Ni/Co3O4, a non-precious metal catalyst was used for the first time in the catalytic conversion of 5-hydroxymethylfurfural (HMF) to 2,5-dimethylfuran (DMF). Under relatively mild conditions (130 °C, 1.0 MPa), as high as 76% yield of DMF was achieved. The addition of Ni not only prevented the formation of by-products, which happened due to the over-reduction of Co3O4 during hydrogenolysis, but also enhanced the reusability of Ni/Co3O4, and the catalyst could be reused for 6 times without loss of activity.A non-precious metal catalyst, Ni/Co3O4 prepared with the hydrothermal method was used for the first time in the catalytic conversion of 5-hydroxymethylfurfural (HMF) to 2,5-dimethylfuran (DMF) and exhibited excellent catalytic performance.Download full-size image
Co-reporter:Xuewang Han, Chaoqun Li, Yong Guo, Xiaohui Liu, Yongguang Zhang, Yanqin Wang
Applied Catalysis A: General (25 September 2016) Volume 526() pp:
Publication Date(Web):25 September 2016
DOI:10.1016/j.apcata.2016.07.011
•N-doped carbon supported Pt catalyst was prepared using hydrothermal and impregnation methods.•Pt/C-EDA-x exhibited high FDCA selectivity under base-free conditions.•Nature of N-doped carbon materials were identified by XPS and CO2-TPD.A new kind of N-doped carbon supported Pt catalyst (Pt/C) has been prepared for the selective oxidation of 5-Hydroxymethylfurfural (HMF) to 2,5-Furandicarboxylic Acid (FDCA) in base-free conditions. The catalyst (Pt/C-EDA-x) prepared by using ethylenediamine (EDA) as nitrogen source showed higher activity than those prepared by N,N-dimethylaniline (DMA), ammonia (NH3) or acetonitrile (ACN) as nitrogen sources. The Pt/C-EDA-4.1 catalyst showed the highest activity in the oxidation of HMF to FDCA and as high as 96.0% FDCA was obtained under optimal reaction conditions (110 °C, 1.0 MPa O2, 12 h). The samples were characterized by XRD, XPS, CO2-TPD, TEM, SEM, and elemental analysis. XPS results showed that the pyridine-type nitrogen (N-6) played a key role in the selective oxidation of HMF, which can be attributed to the basicity of N-6 site. CO2-TPD measurements also showed that the involving of N elements in catalyst preparation introduced a new kind of medium basic site on the support surface. The influence of reaction time, catalyst dosage, and temperature on the HMF oxidation to FDCA catalyzed by Pt/C-EDA-4.1 was studied.Download high-res image (186KB)Download full-size image
Co-reporter:Baohua Zhang, Jiawen Ren, Xiaohui Liu, Yun Guo, Yanglong Guo, Guanzhong Lu, Yanqin Wang
Catalysis Communications (10 March 2010) Volume 11(Issue 7) pp:629-632
Publication Date(Web):10 March 2010
DOI:10.1016/j.catcom.2010.01.010
A novel carbon-based solid-acid catalyst was simply prepared for the first time by the thermal treatment of p-toluenesulfonic acid (TsOH) with d-glucose at 180 °C in a sealed autoclave and it was proved to have high acidity and to be a highly efficient solid-acid catalyst in the reactions such as esterification of succinic acid with ethanol.
Co-reporter:Yu Zhang, Jianjian Wang, Jiawen Ren, Xiaohui Liu, Xiangcheng Li, Yinjiang Xia, Guanzhong Lu and Yanqin Wang
Catalysis Science & Technology (2011-Present) 2012 - vol. 2(Issue 12) pp:NaN2491-2491
Publication Date(Web):2012/08/02
DOI:10.1039/C2CY20204B
By using cetyltrimethylammonium bromide (CTAB) as the template, a series of mesoporous niobium phosphates were synthesized at different pH values in an aqueous solution. Techniques such as small-angle X-ray diffraction, transmission electron microscopy (TEM) and N2 sorption technique were employed to characterize the mesoporous structures of thus-synthesized materials, EDAX to detect the composition, FTIR and solid state 31P MAS NMR to investigate the framework information, while their acidic properties were analyzed using NH3-TPD and pyridine-FTIR. Samples prepared at neutral to acidic conditions exhibited high surface area (213–297 m2 g−1), narrow pore size distribution (3–4 nm) and a great number of strong Lewis and Brönsted acid sites. These materials exhibited excellent activity in the dehydration of fructose to 5-hydroxymethylfurfural (HMF) in water. The maximum HMF yield reached 45% under 130 °C with a reaction time of 0.5 h and the yield slightly decreased to 32% after five cycles and the five-cycled catalyst can be almost regenerated by calcination at 500 °C with the yield of 40%. The excellent catalytic activity obtained in the aqueous phase can be attributed to its high acid site density and the tolerance to water.
Co-reporter:Xiangcheng Li, Qineng Xia, Van Chuc Nguyen, Kaihao Peng, Xiaohui Liu, Nadine Essayem and Yanqin Wang
Catalysis Science & Technology (2011-Present) 2016 - vol. 6(Issue 20) pp:NaN7596-7596
Publication Date(Web):2016/09/15
DOI:10.1039/C6CY01628F
An efficient and selective production of 5-hydroxymethylfurfural (HMF) from carbohydrates is achieved in the presence of mesoporous AlSiO catalysts in a THF/H2O–NaCl biphasic system. These mesoporous AlSiO catalysts are prepared by a facile sol–gel method and have tunable acidity. Their acidic sites are characterized and quantified by NH3-TPD, microcalorimetry of NH3 adsorption and Py-FTIR, then correlated with the catalytic isomerization and dehydration of glucose to HMF. The detailed studies show that the AlSiO-20 catalyst with a Si/Al ratio of 18 is favorable for HMF production due to its inherently high surface area, high amounts of acid sites and a suitable Brønsted/Lewis acid ratio. Over the AlSiO-20 catalyst, an HMF yield of 63.1% is obtained at 160 °C for 1.5 h in the biphasic THF/H2O–NaCl medium with 10 wt% glucose in water. Further conducting the amplification experiment 30 times, the HMF yield still reaches 60.2% and the yield has no obvious decline after four catalytic cycles; this is the best result for an amplification experiment of HMF from glucose over a heterogeneous catalyst so far. After separation, HMF can be used for the production of 2,5-furandicarboxylic acid (FDCA) and as high as 95% FDCA yield is obtained over the Pt/C catalyst. Furthermore, the AlSiO catalyst demonstrates excellent activity in the conversion of disaccharides, polysaccharides and even lignocellulosic biomass, indicating it would be a promising catalyst for the conversion of glucose and glucose-based carbohydrates to HMF in industry applications.
Co-reporter:Xin Gu, Haixiang Tao, Wolfgang Schmidt, Guanzhong Lu and Yanqin Wang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 6) pp:NaN2477-2477
Publication Date(Web):2011/12/22
DOI:10.1039/C1JM13400K
Hollow mesoporous aluminosilicate particles have been synthesized through a one-pot synthesis without using any cavity-forming template. The hollow particles have mesoporous shells with surface areas up to 1300 m2 g−1. The thickness of the shell can be adjusted from about 30 nm to 50 nm by tuning the molar Si/Al ratio and/or variation of the time of hydrothermal treatment. EDX analysis (element mapping) revealed a certain zoning of aluminum in the amorphous aluminosilicate particles investigated. There is an enrichment of Al on the outside of the particles close to the surface. The presence of aluminum appeared to be the key factor for the inhomogeneous dissolution of the aluminosilicate (dissolution of silicon-enriched cores) that leads to the formation of hollow particles.
Co-reporter:Xin Gu, Weimo Zhu, Chunjiang Jia, Rui Zhao, Wolfgang Schmidt and Yanqin Wang
Chemical Communications 2011 - vol. 47(Issue 18) pp:NaN5339-5339
Publication Date(Web):2011/03/28
DOI:10.1039/C0CC05800A
Highly ordered mesoporous NiFe2O4 with excellent microwave absorption properties has been synthesized by using mesoporous silica (KIT-6) as a hard template.
Co-reporter:Xin Gu, Tianlong Jiang, Haixiang Tao, Shutian Zhou, Xiaohui Liu, Jiawen Ren, Yanqin Wang, Guanzhong Lu and Wolfgang Schmidt
Journal of Materials Chemistry A 2011 - vol. 21(Issue 3) pp:NaN886-886
Publication Date(Web):2010/11/12
DOI:10.1039/C0JM01973A
Hydrothermally highly stable mesoporous aluminosilicate spheres with radial channels were synthesized in the CTAB–NaF–TPAOH system through a one-step procedure at high aging temperature. The characterization by transmission electron microscopy (TEM), X-ray diffraction (XRD), nitrogen adsorption/desorption analysis, 27Al MAS solid state NMR spectroscopy, pyridine adsorption FT-IR combined with the typical hydrothermal treatments showed that this kind of material exhibited large surface area, specific pore arrangement, strong acidity and high hydrothermal stability. Detailed studies suggest that F− ions direct the perpendicular arrangement of aluminosilicate clusters during the hydrothermal treatment at 160 °C, while TPA+ stabilized the structure. Both F− and TPA+ ions are considered to improve the acidity and hydrothermal stability of this material through coordination of framework atoms, thus, enhancing the condensation of Si–O–Si bonds in the amorphous pore walls. Due to the accessible radial pore arrangement and high acidity, the catalytic activity for Friedel–Crafts alkylation of toluene with benzyl alcohol was excellent with 100% conversion of benzyl alcohol.
Co-reporter:Rong Jia, Jiawen Ren, Xiaohui Liu, Guanzhong Lu and Yanqin Wang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 29) pp:NaN11201-11201
Publication Date(Web):2014/06/11
DOI:10.1039/C4TA01836B
A new type of sulfonated carbon material with amphiphilic properties was synthesized by the hydrothermal carbonization of a mixture of furfural–sodium dodecylbenzene sulfonate at 180 °C in an autoclave. The addition of SDBS is necessary for the production of materials with long carbon chains and is possibly used to improve the solubilization of long carbon-chain and steric compounds such as pivalic acid. The resulting material was characterized by N2 adsorption, XPS, 13C NMR, XRD and FTIR. The synthesized material was proven to be a highly efficient solid-acid catalyst in reactions such as the esterification of pivalic acid with alcohols, and catalytic performance much better than that of conventional solid acid catalysts, e.g. Amberlyst-15 and Nafion resin, was observed.
Co-reporter:Wenjie Xu, Haifeng Wang, Xiaohui Liu, Jiawen Ren, Yanqin Wang and Guanzhong Lu
Chemical Communications 2011 - vol. 47(Issue 13) pp:NaN3926-3926
Publication Date(Web):2011/02/23
DOI:10.1039/C0CC05775D
A new strategy was developed for the direct conversion of furfural to 1,5-pentanediol by the hydrogenolysis of the furan ring under mild conditions based on Pt/Co2AlO4 catalyst. This is the first report of the direct catalytic conversion of furfural to 1,5-pentanediol with high yield.
Co-reporter:Haixiang Tao, Hong Yang, Yanhui Zhang, Jiawen Ren, Xiaohui Liu, Yanqin Wang and Guanzhong Lu
Journal of Materials Chemistry A 2013 - vol. 1(Issue 44) pp:NaN13827-13827
Publication Date(Web):2013/10/07
DOI:10.1039/C3TA12989F
The sole presence of relatively small micropores in zeolite catalysts strongly influences the mass transfer and catalytic conversion of bulky molecules. Herein, we report a novel synthesis route for the confined synthesis of hierarchical MFI zeolite microspheres with nanorod oriented-assembled structures for the first time via the hydrothermal crystallization of a carbon–silica composite monolith. The growth of such unique zeolite microspheres undergoes a reversed crystal-growth route. Crystallization started on the outer surface of the amorphous particles, then extended to the core and finally resulted in nanorod oriented-assembled structures, due to the confined-space effect of carbon in the carbon–silica monolith. The novel hierarchical zeolite microspheres (5–10 μm), including Silicalite-1, ZSM-5 and TS-1, composed of oriented-assembled nanorods (50–100 nm in width) are easy for separation and have inter-crystalline mesoporous networks between the nanorods; the latter are favourable for mass transfer. More importantly, the hierarchical zeolite microspheres Hier-ZSM-5 and Hier-TS-1 show much higher catalytic activities for bulky substrate conversion than the conventional ZSM-5 and TS-1, respectively. Thus, the novel hierarchical zeolite microspheres reported here show a great potential for industrial applications.
