Co-reporter:Xiao Kong, Yifeng Zhu, Hongyan Zheng, Yulei Zhu, and Zhen Fang
ACS Sustainable Chemistry & Engineering December 4, 2017 Volume 5(Issue 12) pp:11280-11280
Publication Date(Web):October 24, 2017
DOI:10.1021/acssuschemeng.7b01813
Co-reporter:Yifeng Zhu, Xiao Kong, Junqing Yin, Rui You, Bin Zhang, Hongyan Zheng, Xiaodong Wen, Yulei Zhu, Yong-Wang Li
Journal of Catalysis 2017 Volume 353(Volume 353) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.jcat.2017.07.030
•Atomically dispersed (83%) but high-loading (15 wt%) Cu on SiO2 was realized.•Covalent CuOSi bonding alters the atomically dispersed and valence states.•The bonding is enabled by a simple urea assistant hydrothermal-deposition method.•CuOSi bonding boosts the intrinsic efficiency by one- to two- orders-of-magnitude.•Transition metals (Cu, Zn, Ni, Co and Mn) can form the bonding via the method.Being a suitable way for achieving the maximum efficiency of atoms, the atomically dispersed metals are playing an ever-increasingly important role in bridging heterogeneous and homogeneous catalysis. It is extremely challenging for dispersing metals in atomic-scales as the applicable high-loading catalysts for industry. The reducible and defective supports or metal surfaces are commonly chosen for anchoring the metals. We here report that atomically-dispersed but high-loading (15 wt%) metals were achieved by covalent-bonding to irreducible SiO2 (though silanol groups) which is realized by a simple urea hydrolysis assistant hydrothermal-deposition method. The CuOSi bonding tailors the structural and electronic states of catalyst by maximum of atom efficiency and tuning electronic effects. The intrinsic performance of CO hydrogenation was thus boosted by one- to two- orders-of-magnitude in comparison with impregnated and precipitated catalysts. The choices of metals include Cu, Zn, Ni, Co and Mn, showing potentials for a category of applied materials.Download high-res image (236KB)Download full-size image
Co-reporter:Qingwei Meng, Dongbo Cao, Guoyan Zhao, Chengwu Qiu, Xingchen Liu, Xiaodong Wen, Yulei Zhu, Yongwang Li
Applied Catalysis B: Environmental 2017 Volume 212(Volume 212) pp:
Publication Date(Web):5 September 2017
DOI:10.1016/j.apcatb.2017.04.069
•Highly selective decarbonylation of HMF over Pd/Al2O3 in water-containing system.•The hydrogen bonds between hydroxyl of FOL and water hinder dehydrogenation to form FAL and furan.•Hydrogenolysis reactions mainly follow the metal-acid synergistic mechanism.•The hydrogen bonds between hydroxyl on Al2O3 surface and water decrease the acidity of Pd/Al2O3.•Hydrogenolysis and etherification side reactions were suppressed.Highly selective decarbonylation of 5-hydroxymethylfurfural (HMF) to furfuryl alcohol (FOL) was originally realized by adding water to organic solvent. Side reactions such as hydrogenolysis, dehydrogenation and etherification could be effectively suppressed by introducing appropriate amount of water in pure organic solvent. Based on DFT calculations, hydrogen bonds between hydroxymethyl groups and water hinder the dehydrogenation of FOL to furfural (FAL) and furan. On the other hand, in situ water-pyridine-FTIR measurements revealed that the hydrogen bonding interaction between water and the hydroxyl groups on γ-Al2O3 surface decrease the acidity of Pd/Al2O3 and suppresses side reactions such as hydrogenolysis and etherification. Therefore, adding water to organic solvent could be a strategy for the protection of hydroxyl groups.Download high-res image (100KB)Download full-size image
Co-reporter:Fang Dong;Haijun Zhao;Zhicheng Tang
Catalysis Science & Technology (2011-Present) 2017 vol. 7(Issue 9) pp:1880-1891
Publication Date(Web):2017/05/09
DOI:10.1039/C7CY00233E
The design and development of heterogeneous catalysts is very critical for the synthesis of various chemicals and fuels derived from superfluous biomass. The synthesis of biofuel 2-methylfuran typically derives from the conversion of the formyl group of biomass-derived furfural, because this process is very valuable in terms of the amelioration and remission of the environment and energy crisis. Herein, we designed a series of bifunctional catalysts formed in line with the spatial restriction strategy by anchoring copper nanoparticles (Cu NPs) on phyllosilicate-like structures to enhance copper dispersion and provide properly assembled Lewis acid sites to promote the hydrogenation and hydrogenolysis of the formyl group in furfural, and first applied them to the conversion of the formyl group with high efficiency. However, the modulation of the Cu–Si molar ratio is extremely critical to the possible reduction of metal consumption, full exploitation of the prerequisite metal sites and great improvement of activity. In this work, the catalyst with a Cu–Si molar ratio (actual value = 0.33) lower than that of the industrial catalyst (theoretical value = 1.0) exhibited higher yields of the intermediate furfuryl alcohol (yield = 83.4%) and the desired product 2-methylfuran (yield = 95.5%). More importantly, with the continuous increase of the Cu–Si molar ratio, it is discovered that Cu dispersion regularly decreased and the size of the Cu NPs sequentially increased, and the change of assembled Lewis acid sites surprisingly kept pace with the integrity of the layered structure, as revealed by a series of detailed characterization studies.
Co-reporter:Xiaohai Yang;Hongmei Chen;Qingwei Meng;Hongyan Zheng;Yong Wang Li
Catalysis Science & Technology (2011-Present) 2017 vol. 7(Issue 23) pp:5625-5634
Publication Date(Web):2017/11/27
DOI:10.1039/C7CY01284E
Cu/ZnO catalysts primarily derived from aurichalcite with Cu/Zn = 0.4–1.1 (mol/mol) were prepared via “decreased pH” coprecipitation method and introduced in hydrogenation of furfural to furfuryl alcohol. The “precursor effect” was clearly confirmed and the catalyst with a Cu/Zn = 0.8 provided the best conversion and TOF. Catalysts were characterized via XRD, FT-IR, N2O titration, TEM, H2-TPR, XPS and AES. The size of Cu nanoparticles and Cu–ZnO interactions were systematically investigated and were found to remarkably influence catalytic activity of the catalysts. Consequently, the best catalytic performance for the catalyst with Cu/Zn = 0.8 was due to the suitable Cu particle size (8 nm) and strong metal–support interactions (SMSI), acting as the Cu–ZnO synergy.
Co-reporter:Jinglei Cui, Jingjing Tan, Tiansheng Deng, Xiaojing Cui, Yulei Zhu and Yongwang Li
Green Chemistry 2016 vol. 18(Issue 6) pp:1619-1624
Publication Date(Web):29 Oct 2015
DOI:10.1039/C5GC01948F
Furfural is one of the most valuable biomass-derived platform molecules which is primarily produced from hemicellulose. It is of significant importance but still highly challenging to produce furfural from hexoses, which are extensively distributed in nature. In this paper, carbohydrates (cellulose, starch, inulin, maltose, sucrose, glucose and fructose) were transformed into furfural efficiently over Hβ zeolite in a γ-butyrolactone–water solvent. The key process for converting hexoses into furfural is the selective cleavage of the C–C bond in hexoses to pentoses. The Hβ zeolite was discovered to induce the formation of acyclic hexoses, and the synergy between Hβ and solvent enables the selective C–C bond cleavage of acyclic hexoses into pentoses and promotes the subsequent dehydration of pentoses into furfural. Furfural yields for converting fructose and glucose reached 63.5% and 56.5% under milder conditions (150 °C), respectively. Moreover, a favorable yield of 38.5% for furfural can be achieved by direct conversion of cellulose.
Co-reporter:Qingwei Meng, Chengwu Qiu, Guoqiang Ding, Jinglei Cui, Yulei Zhu and Yongwang Li
Catalysis Science & Technology 2016 vol. 6(Issue 12) pp:4377-4388
Publication Date(Web):02 Feb 2016
DOI:10.1039/C5CY02248G
A series of Pd/Al2O3 catalysts with different alkali earth metals (Mg, Ca, Sr, Ba) and varying Sr loadings (1.8, 3.5, 5.3, 7 and 8.8 wt%) were investigated for 5-hydroxymethylfurfural (HMF) decarbonylation. The alkali earth metal and content were demonstrated to have profound influences on the metal dispersion, electron density of the metal, acid–base properties of the catalyst, and catalytic performance. The Pd3Sr/Al2O3 catalyst exhibited the highest initial activity and furfuryl alcohol selectivity, achieving a yield of 92%. The key to high decarbonylation selectivity is the suppression of hydrogenolysis and etherification side reactions through the attenuation of the acidity of catalysts. Successful catalytic activity not only lies in the increased metallic surface area, but is also affected by the adsorption properties of the carbonyl group and the poisoning CO produced. The catalytic activity is linearly correlated to the surface metallic area at low modifier loading over PdM/Al2O3 catalysts. But along with further increased metallic surface area over PdXSr/Al2O3, HMF conversion initially increased, reaching a plateau over Pd3Sr/Al2O3 and then decreased with increasing Sr loading. A synergistic effect between the Sr species and metallic Pd was proposed, which promoted the migration of carbonyl adsorption from the support to the surface Pd through the electron donation of Sr species to Al2O3 and metallic Pd.
Co-reporter:Jingjing Tan, Jinglei Cui, Guoqiang Ding, Tiansheng Deng, Yulei Zhu and Yong-wang Li
Catalysis Science & Technology 2016 vol. 6(Issue 5) pp:1469-1475
Publication Date(Web):25 Sep 2015
DOI:10.1039/C5CY01374G
Efficient aqueous hydrogenation of levulinic acid over supported catalysts is of fundamental and industrial interest but is highly challenging. For Ru/γ-Al2O3 catalysts, the primary problems are low activity and stability that arose from the inhomogeneous dispersion of Ru and the unstable nature of γ-Al2O3 in water. In this work, an integrated strategy was proposed for developing a highly active and stable catalyst for aqueous hydrogenation of LA to GVL. By modification with 3-aminopropyltriethoxysilane (KH550), the abundant surface Al–OH groups of γ-Al2O3 were transformed into a stable Al–O–Si structure, while ruthenium active centres were bonded to a γ-Al2O3 surface via coordination with amino ligands of KH550. This modification favours the formation of highly dispersed Ru centres with an electron-rich state, leading to a superior activity at temperatures as low as 25 °C (GVL yield of 99.1%, TOF of 306 h−1) and high stability.
Co-reporter:Fang Dong, Guoqiang Ding, Hongyan Zheng, Xiaoming Xiang, Linfeng Chen, Yulei Zhu and Yongwang Li
Catalysis Science & Technology 2016 vol. 6(Issue 3) pp:767-779
Publication Date(Web):20 Aug 2015
DOI:10.1039/C5CY00857C
Cu/SiO2 catalysts were synthesized by different methods, which greatly influenced their texture and the catalytic performance. The AE-Cu/SiO2 catalyst was prepared via the ammonia evaporation method and showed a 95.5% yield for 2-methylfuran (a promising fuel additive) because of the cooperative effects of surface Cu0, Cu+ species and acid sites, which respectively stemmed from the reduction of highly dispersed CuO species, copper species that fiercely interacted with the support SiO2, and the special structure. The ammonia evaporation method favored the formation of a copper phyllosilicate phase with a lamellar structure, which could provide a large number of Cu nanoparticles and acid sites and further improve the activity and selectivity. Crucially, the stability of the AE-Cu/SiO2 catalyst (>210 h) was also significantly improved due to the enhanced copper–silicon interactions, which could immobilize copper particles and resist the fast transmigration (aggregation and loss) of copper particles in the thermal treatment process. In contrast, the CP-Cu/SiO2 catalyst was synthesized via the conventional precipitation method and presented poor activity and stability toward 2-methylfuran because of large copper particles, severe aggregation and a loss of copper species during reaction. Compared with the conventional CP-Cu/SiO2 catalyst, the use of the AE-Cu/SiO2 catalyst in the synthesis of the biofuel 2-methylfuran could not only improve the yield of the desired product, but also decrease by at least 20 °C the reaction temperature which is propitious for prolonging the lifetime of the Cu/SiO2 catalyst.
Co-reporter:Xiaomin Xiang, Jinglei Cui, Guoqiang Ding, Hongyan Zheng, Yulei Zhu, and Yongwang Li
ACS Sustainable Chemistry & Engineering 2016 Volume 4(Issue 9) pp:4506
Publication Date(Web):August 22, 2016
DOI:10.1021/acssuschemeng.6b01411
Selective conversion of fructose to fuels and fine chemicals is an important step for biomass utilization. In this paper, direct conversion of fructose to 2,5-dihydroxymethylfuran and 2,5-dimethylfuran was first realized over combined HY zeolite and inexpensive hydrotalcite (HT)-Cu/ZnO/Al2O3 in a fixed-bed reactor. The cooperative effect of HY zeolite and γ-butyrolactone solvent facilitated the dehydration of fructose into 5-hydroxymethylfurfural. By adjusting the hydrogenation temperature for HMF over HT-Cu/ZnO/Al2O3 catalyst, high yields of 2,5-dihydroxymethylfuran (48.2%) at 140 °C and 2,5-dimethylfuran (40.6%) at 240 °C were obtained, respectively.Keywords: 5-Hydroxymethylfurfural; Biomass; HT-Cu/ZnO/Al2O3; HY zeolite; γ-Butyrolactone
Co-reporter:Hanhan Fan, Jingjing Tan, Yulei Zhu, Hongyan Zheng, Yongwang Li
Journal of Molecular Catalysis A: Chemical 2016 Volume 425() pp:68-75
Publication Date(Web):15 December 2016
DOI:10.1016/j.molcata.2016.09.033
•A new catalyst of Ru-NH2-SiO2 synthesized by modification and immobilization is developed.•The Ru-NH2-SiO2 catalyst exhibits a superior low temperature catalytic activity in the hydrogenation of DMO to MG.•The nanoscale sized Ru centers with high dispersion and electron-rich state contribute to the high catalytic activity.Highly active and stable catalysts for hydrogenation of dimethyl oxalate (DMO) to methyl glycolate (MG) were desirable but highly challengeable. In this study, a kind of immobilized Ru based catalyst for the hydrogenation of DMO has been developed. The catalyst was synthesized by covalently bonding a ruthenium complex onto the modified-SiO2 surface, which was modified by 3-aminopropyltriethoxysilane (KH550), through coordination interaction with aminosilane ligands. Compared with the traditional Ru/SiO2 catalyst, the immobilized Ru-NH2-SiO2 catalyst exhibits significantly enhanced catalytic performance and high stability towards hydrogenation of dimethyl oxalate to MG at temperatures as low as 80 °C. The yield of MG was 86.8% over Ru-NH2-SiO2 catalyst, while the yield of MG was only 34.5% over Ru/SiO2 catalyst. A series of characterization revealed that the excellent catalytic performance of Ru-NH2-SiO2 was resulted from the superior dispersion of Ru NPs on the surface of support and the electron-rich state of Ru centers.Efficient hydrogenation of DMO to MG over highly active and stable immobilized ruthenium catalyst with a MG yield of 86.8 mol% at 80 °C.
Co-reporter:Qingwei Meng, Hongyan Zheng, Yulei Zhu, Yongwang Li
Journal of Molecular Catalysis A: Chemical 2016 Volume 421() pp:76-82
Publication Date(Web):September 2016
DOI:10.1016/j.molcata.2016.05.012
•An extensive product distribution is firstly examined in decarbonylation of HMF.•The H2 source was determined to be the hydroxymethyl dehydrogenation.•The elimination path of CH2OH is sequential dehydrogenation and decarbonylation.•The reactivity of the main intermediates was separately investigated.•A comprehensive reaction pathway for HMF decarbonylation is proposed.An extensive product distribution is firstly examined in the process of 5-hydroxymethylfurfural (HMF) decarbonylation over Pd-based catalysts and some interesting results are obtained. The main side reactions are due to the high activity of the furan ring-branched hydroxymethyl, which could go through hydrogenolysis, dehydrogenation and etherification. The H2 source was carefully explored and determined to be the hydroxymethyl dehydrogenation. The reactivity of the main intermediates was separately investigated and their evolution pathway was obtained. Noticeably, it is demonstrated that the elimination of the furanic ring-branched hydroxymethyl (in HMF or furfuryl alcohol) is completed by sequential dehydrogenation and decarbonylation via the intermediate of aldehyde (2, 5-diformylfuran or furfural). A comprehensive reaction pathway for HMF decarbonylation is proposed, which is significant for designing highly selective decarbonylation catalysts.
Co-reporter:Dr. Jinglei Cui;Dr. Jingjing Tan;Dr. Xiaojing Cui; Yulei Zhu;Dr. Tiansheng Deng;Dr. Guoqiang Ding; Yongwang Li
ChemSusChem 2016 Volume 9( Issue 11) pp:1259-1262
Publication Date(Web):
DOI:10.1002/cssc.201600116
Abstract
An efficient process was designed for the synthesis of furfuryl alcohol and 2-methylfuran from xylose using a continuous fixed-bed reactor over a catalyst combining Hβ zeolite and Cu/ZnO/Al2O3 in γ-butyrolactone (GBL)/water as solvent. The cooperative effect of Hβ zeolite and GBL facilitated the dehydration of xylose and enhanced largely the furfural yield. The production of furfuryl alcohol and 2-methylfuran can be simply tuned by changing the hydrogenation temperature for furfural over the Cu/ZnO/Al2O3 catalyst. The yield for furfuryl alcohol reached 87.2 % at 150 °C whereas a yield of 86.8 % was achieved for 2-methylfuran at 190 °C.
Co-reporter:Xiao Kong, Yifeng Zhu, Hongyan Zheng, Xianqing Li, Yulei Zhu, and Yong-Wang Li
ACS Catalysis 2015 Volume 5(Issue 10) pp:5914
Publication Date(Web):August 27, 2015
DOI:10.1021/acscatal.5b01080
Hydrogenolysis of carbon–oxygen bonds is a versatile synthetic method, of which hydrogenolysis of bioderived 5-hydroxymethylfurfural (HMF) to furanic fuels is especially attractive. However, low-temperature hydrogenolysis (in particular over non-noble catalysts) is challenging. Herein, nickel nanoparticles (NPs) inlaid nickel phyllosilicate (NiSi-PS) are presented for efficient hydrogenolysis of HMF to yield furanic fuels at 130–150 °C, being much superior with impregnated Ni/SiO2 catalysts prepared from the same starting materials. NiSi-PS also shows a 2-fold HMF conversion intrinsic rate and 3-fold hydrogenolysis rate compared with the impregnated Ni/SiO2. The superior performance originated from the synergy of highly dispersed nickel NPs and substantially formed acid sites due to coordinatively unsaturated Ni (II) sites located at the remnant nickel phyllosilicate structure, as revealed by detailed characterizations. The model reactions over the other reference catalysts further highlighted the metal–acid synergy for hydrogenolysis reactions. NiSi-PS can also efficiently catalyze low-temperature hydrogenolysis of bioderived furfural and 5-methylfurfural, demonstrating a great potential for other hydrogenolysis reactions.Keywords: 5-hydroxymethylfurfural; heterogeneous catalysis; hydrogenolysis; nickel; silica
Co-reporter:Jingjing Tan, Jinglei Cui, Xiaojing Cui, Tiansheng Deng, Xianqing Li, Yulei Zhu, and Yongwang Li
ACS Catalysis 2015 Volume 5(Issue 12) pp:7379
Publication Date(Web):November 5, 2015
DOI:10.1021/acscatal.5b02170
Low-temperature efficient hydrogenation of C═O bonds in various compounds, which is one of the most important processes for producing fuels and chemicals, is of fundamental interest but remains a significant challenge. The primary problem is a lack of heterogeneous catalyst systems that are highly active at ambient or low temperatures. This paper describes an efficient strategy for designing a low-temperature hydrogenation catalyst. Ru nanoparticles supported on reduced graphene oxide (Ru/RGO) show remarkable efficiency for hydrogenation of levulinic acid into γ-valerolactone at temperatures as low as −10 °C. The catalyst is also highly active toward low-temperature hydrogenation of C═O bonds in other carbonyl compounds into C–OH bonds, such as furfural, propionaldehyde, 2-pentanone, hydroxyacetone, acetone, acetophenone, cyclohexanone, and benzophenone. X-ray photoelectron spectroscopy and in situ Fourier transform infrared demonstrate that the electron transfer between Ru0 and RGO leads to the formation of an electron-rich state of Ru0 nanoparticles that are highly effective for activating C═O bonds.Keywords: graphene; hydrogenation; levulinic acid; low-temperatrue; water; γ-valerolactone
Co-reporter:Xiao Kong, Runxiao Zheng, Yifeng Zhu, Guoqiang Ding, Yulei Zhu and Yong-Wang Li
Green Chemistry 2015 vol. 17(Issue 4) pp:2504-2514
Publication Date(Web):12 Feb 2015
DOI:10.1039/C5GC00062A
Selective hydrogenation of 5-hydroxymethylfurfural (HMF) is of great importance for future energy and chemical supply. Herein, we propose for the first time that non-noble Ni-Al2O3 catalysts derived from hydrotalcite-like compounds can efficiently and selectively convert HMF into 2,5-dimethylfuran (DMF), 2,5-dimethyltetrahydrofuran (DMTHF) and 2,5-dihydroxymethyltetrahydrofuran (DHMTHF). Homogeneous elemental distributions of the hydrotalcite-like precursor facilitate good dispersion of Ni and Al2O3 species and strong interaction between them over the resulting catalysts. The catalysts therefore exhibited superior reactivity. Through fine modulation of surface metal–acid bifunctional sites and control of reaction conditions, high yields of DMF (91.5%), DMTHF (97.4%) and DHMTHF (96.2%) can be diversely achieved. The results demonstrate the feasibility of Ni catalysts for selective hydrogenation of CO, CC and C–O bonds, which have great potential for biomass utilization.
Co-reporter:Chengwei Liu, Chenghua Zhang, Sikai Sun, Kangkai Liu, Shunli Hao, Jian Xu, Yulei Zhu, and Yongwang Li
ACS Catalysis 2015 Volume 5(Issue 8) pp:4612
Publication Date(Web):July 7, 2015
DOI:10.1021/acscatal.5b00800
A series of Pd–WOx/Al2O3 catalysts with different contents of WOx were prepared by stepwise incipient wetness impregnations. The influence of WOx on the physicochemical properties of Pd–WOx/Al2O3 catalysts, as well as their catalytic performance for the hydrogenolysis of glucose to 1,2-propanediol (1,2-PDO), was investigated. At low surface W density (0.3–2.1 W nm–2), distorted isolated WOx and oligomeric WOx are present on the Pd–WOx/Al2O3 catalysts. Furthermore, isolated WO4 are the dominating species on the Pd–WOx(5%)/Al2O3 catalyst. When the W density increased to 3.1 W nm–2, polymeric WOx species are dominant on the Pd–WOx(30%)/Al2O3 catalyst. The Pd surface area decreased while the acid amount increased with increasing W density. Furthermore, increased Lewis acid sites are provided by isolated WO4 and oligomeric WOx species whereas increased Brønsted acid sites exist on polymeric WOx species. Lewis acid sites promote glucose isomerization to fructose, which is an intermediate in glucose hydrogenolysis to 1,2-PDO. Metal sites catalyze C═O hydrogenation and C–C hydrogenolysis, which avoid the coke formation on catalysts. 1,2-PDO selectivity is dependent on the synergy of Lewis acid and metal sites; however, Brønsted acid sites have no contribution to the 1,2-PDO production. Typically, the Pd–WOx(5%)/Al2O3 catalyst possessing the optimal balance of Lewis acid and the metal site shows a 1,2-PDO selectivity of 60.8% at a glucose conversion of 92.2% and has a lifetime of over 200 h.Keywords: 1,2-propanediol; biomass; fructose; glucose; hydrogenolysis; isomerization; Pd−WOx/Al2O3; WOx
Co-reporter:Jinglei Cui, Jingjing Tan, Tiansheng Deng, Xiaojing Cui, Hongyan Zheng, Yulei Zhu and Yongwang Li
Green Chemistry 2015 vol. 17(Issue 5) pp:3084-3089
Publication Date(Web):26 Mar 2015
DOI:10.1039/C5GC00110B
The carbohydrates (cellulose, starch, inulin, maltose, sucrose, glucose and fructose) were converted efficiently into γ-valerolactone (GVL) over combined H3PW12O40 and Ru/TiO2 catalysts under mild conditions. The basicity of oxygen-containing solvents had a remarkable effect on the acid strength of H3PW12O40, which resulted in great variation in the yield of GVL. H3PW12O40 was more effective in 20 vol% water/γ-butyrolactone than in pure water and other water/organic solvents (methanol, ethanol and 1,4-dioxane). GVL yields for inulin and fructose reached 70.5 mol% and 67.6 mol% respectively. Meanwhile, a GVL yield of 40.5 mol% was achieved for cellulose. In addition, a practical method for catalyst recycling and GVL separation was developed by adding sugar into the reaction mixture. H3PW12O40 and Ru/TiO2 maintained their activity after three recycling runs.
Co-reporter:Yifeng Zhu, Xiao Kong, Hongyan Zheng, Guoqiang Ding, Yulei Zhu and Yong-Wang Li
Catalysis Science & Technology 2015 vol. 5(Issue 8) pp:4208-4217
Publication Date(Web):18 Jun 2015
DOI:10.1039/C5CY00700C
Selective conversion of 5-hydroxymethylfurfural (HMF) can produce sustainable fuels and chemicals. Herein, Cu–ZnO catalysts derived from minerals (malachite, rosasite and aurichalcite) were employed for selective hydrogenation of HMF for the first time. High yields of 2,5-dihydroxymethylfuran (~99.1%) and 2,5-dimethylfuran (~91.8%) were obtained tunably over the catalyst with a Cu/Zn molar ratio of 2, due to the well-dispersed metal sites tailored by mineral precursors, well-controlled surface sites and optimized reaction conditions. The relationship between catalytic performance and catalyst properties was elucidated by characterization based on the composition and the structural and surface properties, and catalytic tests. The catalyst can also be extended to selective hydrogenation of other bio-derived molecules (furfural and 5-methylfurfural) to target products. The construction of mineral-derived Cu–ZnO catalysts and the revelation of the structure–performance relationship can be applied to further rational design and functionalization of non-noble Cu catalysts for selective conversion of bio-derived compounds.
Co-reporter:Shanhui Zhu, Xiaoqing Gao, Yulei Zhu, Weibin Fan, Jianguo Wang and Yongwang Li
Catalysis Science & Technology 2015 vol. 5(Issue 2) pp:1169-1180
Publication Date(Web):30 Oct 2014
DOI:10.1039/C4CY01148A
A highly efficient and robust Cu/SiO2 catalyst from a pure-phase copper phyllosilicate precursor was successfully fabricated by the ammonia evaporation hydrothermal (AEH) method. The impregnation (IM) Cu/SiO2 catalyst was prepared for comparison. The structure, morphologies, thermal stability and surface chemical state of these catalysts were comprehensively characterized by ICP, BET, XRD (in situ XRD), N2O chemisorption, H2-TPR, IR and Raman spectroscopy, TEM and XPS. Compared to the IM sample, the AEH catalyst was exceedingly highly active and stable (300 h) for glycerol hydrogenolysis to 1,2-propanediol. The unprecedented catalytic performance was attributed to the strong interaction between Cu and SiO2 species derived from copper phyllosilicate, well-dispersed Cu nanoparticles and the cooperative effect of Cu0 and Cu+. Moreover, active Cu0 species were identified as the primary active sites for glycerol hydrogenolysis, as corroborated by the strong correlation between 1,2-propanediol yield and Cu surface area.
Co-reporter:Dr. Fang Dong; Yulei Zhu;Dr. Guoqiang Ding;Dr. Jinglei Cui;Xianqing Li; Yongwang Li
ChemSusChem 2015 Volume 8( Issue 9) pp:1534-1537
Publication Date(Web):
DOI:10.1002/cssc.201500178
Abstract
One-step direct conversion of biomass-derived furfural to 2-methyltetrahydrofuran was realized under atmospheric pressure over a dual solid catalyst based on two-stage-packed Cu–Pd in a reactor; this is the first report that one-step conversion of furfural resulted in high yield of 2-methyltetrahydrofuran (97.1 %) under atmospheric pressure. This strategy provided a successive hydrogenation process, which avoids high H2 pressure, uses the reactor efficiently, and eliminates the product-separation step. Therefore, it could enhance the overall efficiency as a result of low cost and high yield.
Co-reporter:Jingjing Tan;Jinglei Cui;Dr. Tiansheng Deng;Dr. Xiaojing Cui;Dr. Guoqiang Ding; Yulei Zhu; Yongwang Li
ChemCatChem 2015 Volume 7( Issue 3) pp:508-512
Publication Date(Web):
DOI:10.1002/cctc.201402834
Abstract
A highly efficient and green process for the hydrogenation of biomass-derived levulinic acid (LA) to γ-valerolactone (GVL) has been developed. GVL was obtained in a yield of 99.9 mol % with a turnover frequency as high as 7676 h−1 in aqueous medium by using a Ru/TiO2 catalyst under mild reaction conditions (70 °C). The strong interaction between Ru and TiO2 facilitated both the dispersion of Ru nanoparticles and the stability of the catalyst. In addition, as solvent, water participated in the hydrogenation of LA, which was confirmed by an isotope- labeling experiment with D (D2O). Specifically, the H atom(s) in water took part in the hydrogenation of the CO group of LA, which promoted the catalytic activity and GVL yield remarkably.
Co-reporter:Fang Dong, Yulei Zhu, Hongyan Zheng, Yifeng Zhu, Xianqing Li, Yongwang Li
Journal of Molecular Catalysis A: Chemical 2015 Volume 398() pp:140-148
Publication Date(Web):March 2015
DOI:10.1016/j.molcata.2014.12.001
•Cr-free Cu-catalysts were investigated for the highly efficient conversion of furfural.•The high yield of 2-methylfuran was attributed to synergistic effect of metal and the weak acid sites.•Interactions of copper-support significantly influence the catalytic performance.•The acidic property of Cu-catalysts was closely related to products selectivity in furfural hydrogenation.Our work focuses on exploring Cr-free Cu-catalysts for the highly efficient conversion of biomass-derived furfural to value-added bio-fuel 2-methylfuran. Three supported Cu-catalysts (Cu/SiO2, Cu/Al2O3, and Cu/ZnO) were prepared by the typical precipitation method, and Cu/SiO2 catalyst exhibited the best catalytic performance with an 89.5% yield to 2-MF. A series of characteristic results indicated that the high yield of 2-methylfuran on Cu/SiO2 catalyst was assigned to synergistic effect of metal and the weak acid sites. Among them, Cu/ZnO catalyst exhibited maximum furfuryl alcohol selectivity because of the large Cu particles, while Cu/Al2O3 catalyst had low 2-methylfuran selectivity due to the insufficient weak acid sites. For Cu/SiO2 catalyst, the highly dispersed Cu particles and the strong metal-support interaction are propitious to its superior catalytic activity. Therefore, copper species are composed on different supports as a result of the different interaction of metal-support to affect their catalytic activity, while products selectivity is related to the acidic property of catalyst. In addition, temperature programmed desorption of furfural indicated that the adsorption–desorption properties of catalyst surface species would influence the rate of furfural hydrogenation.
Co-reporter:Shanhui Zhu, Xiaoqing Gao, Yulei Zhu, Yongwang Li
Journal of Molecular Catalysis A: Chemical 2015 Volume 398() pp:391-398
Publication Date(Web):March 2015
DOI:10.1016/j.molcata.2014.12.021
•WOx species existed as monotungstate, polytungstate and crystalline m-WO3 phase.•Addition of WOx to Pt/Al2O3 induced hydrogen spillover.•42.4% 1,3-propanediol yield was achieved over Pt–10WOx/Al2O3.•1,3-Propanediol yield was proportional to the concentration of Brønsted acid sites.•1,2-Propanediol yield was proportional to the concentration of Lewis acid sites.Despite 1,3-propanediol possessing high economic value, its production from glycerol hydrogenolysis is a challenging task. Herein, a series of WOx promoted Pt/Al2O3 catalysts with various WOx contents were prepared and investigated for selective production 1,3-propanediol from glycerol hydrogenolysis. To explore the structure feature, these catalysts were fully characterized by BET, CO chemisorption, HRTEM, XRD (in situ XRD), Raman, NH3–TPD, Py–IR, H2–TPR, and XPS. Among them, Pt–10WOx/Al2O3 achieved the highest 1,3-propanediol yield up to 42.4%, which was ascribed to the large concentration of Brønsted acid sites, strong electronic interaction between Pt with WOx and hydrogen spillover. The strong correlation between 1,3-propanediol yield and Brønsted acid site indicated its essential role for the formation of 1,3-propanediol. Meanwhile the linear correlation between 1,2-propanediol yield and Lewis acid site gave direct evidence that Lewis acid site preferentially generated 1,2-propanediol.
Co-reporter:Yifeng Zhu, Xiao Kong, Xianqing Li, Guoqiang Ding, Yulei Zhu, and Yong-Wang Li
ACS Catalysis 2014 Volume 4(Issue 10) pp:3612
Publication Date(Web):September 4, 2014
DOI:10.1021/cs5009283
Ethanol synthesis from syngas via dimethyl oxalate (DMO) hydrogenation is of crucial importance for environment- and energy-related applications. Herein, we designed the bifunctional Cu nanoparticle (NP) inlaid mesoporous Al2O3 catalyst and first applied it to ethanol synthesis with high efficiency. The catalyst was made based on the spatial restriction strategy by pinning the Cu NPs on mesoporous Al2O3 to conquer the sintering problem and facilitate the stability (>200 h at 270 °C), which has potential values in high-temperature and exothermic reactions. The plentiful pores, highly exposed and properly assembled Cu-acid sites, furnished the catalyst with high ethanol yield (∼94.9%). A structure-sensitive behavior that the intrinsic activity increases with the decreasing NP size was discussed. It was attributed to the change in metal–acid interfacial sites, morphology, and electronic structure and balance of surface Cu0–Cu+ species. The mechanism for DMO hydrogenation to ethanol involving activation of C═O, C–O, and O–H bands was also proposed. As cleavage of these bonds is a versatile tool to utilize bioderived molecules (e.g., polyols), the bifunctional catalysts can also be applied to hydrogenolysis of C–O bonds or etherification of O–H groups to produce various chemicals.Keywords: copper; ethanol synthesis; mesoporous Al2O3; metal-acid; stability; structure−activity relationship
Co-reporter:Yifeng Zhu, Xiao Kong, Dong-Bo Cao, Jinglei Cui, Yulei Zhu, and Yong-Wang Li
ACS Catalysis 2014 Volume 4(Issue 10) pp:3675
Publication Date(Web):September 9, 2014
DOI:10.1021/cs501155x
To develop the high-performance supported metal catalyst for industrial processes, it is highly desirable to elucidate and fully utilize the indispensable support part. Herein, the relationship between catalytic performance and the structure of support ZrO2 was elucidated by comprehensive analysis of the progressive calcination experiments, tests over model catalysts, and various characterizations of catalyst structures. We demonstrated that combination of Cu and tetragonal ZrO2 makes a highly active, selective, and especially stable catalyst for the hydrogenation of dimethyl oxalate to ethylene glycol. To obtain stable Cu particles, the catalyst was annealed at high temperatures (e.g., from 450 to 850 °C). The stable large Cu particles were formed, and the number of exposed Cu sites decreased. Fortunately, support ZrO2 was motivated into the tetragonal phase, compensating for and even improving the activity. Thus, the yield of ethylene glycol was greatly improved from ∼26 to 99%, and a stable performance was achieved (life span of >600 h). The strategy alleviated the dependence of hydrogenation on highly dispersed metal sites and provided an alternative way to enhance the catalytic stability. This simple way simultaneously improved the efficiency and reduced the level of irreversible deactivation due to sintering, which has great potential for industrial applications. Tetragonal ZrO2 also proved to be effective for a series of carbonyl hydrogenations (e.g., esters, aldehydes, ketones, and acids), indicating a general promotion of these reactions by ZrO2.Keywords: catalytic hydrogenation; catalytic support; cooperative effects; copper; stability; zirconia
Co-reporter:Dr. Hongliang Wang;Qingqiang Kong;Dr. Yingxiong Wang;Dr. Tiansheng Deng;Dr. Chengmeng Chen; Xianglin Hou; Yulei Zhu
ChemCatChem 2014 Volume 6( Issue 3) pp:728-732
Publication Date(Web):
DOI:10.1002/cctc.201301067
Abstract
The design of green heterogeneous catalysts for the efficient conversion of biomass into platform molecules is a key aim of sustainable chemistry. Graphene oxide prepared from Hummers oxidation of graphite was proven to be a green and efficient carbocatalyst for the dehydration of fructose into 5-hydroxymethylfurfural (HMF) in some three-carbon and four-carbon alcohol mediated solvent systems. HMF was obtained in up to 87 % yield in 90 vol % isopropanol-mediated DMSO solvent. Some control experiments and analytical data showed that a small number of sulfonic groups and abundance of oxygen-containing groups (alcohols, epoxides, carboxylates) have an important synergic effect in maintaining the high performance of graphene oxide.
Co-reporter:Hongliang Wang, Tiansheng Deng, Yingxiong Wang, Xiaojing Cui, Yongqin Qi, Xindong Mu, Xianglin Hou and Yulei Zhu
Green Chemistry 2013 vol. 15(Issue 9) pp:2379-2383
Publication Date(Web):17 Jul 2013
DOI:10.1039/C3GC41109E
Graphene oxide obtained by the Hummers method was discovered to be an efficient and recyclable acid catalyst for the conversion of fructose-based biopolymers into 5-ethoxymethylfurfural (EMF). EMF yields of 92%, 71%, 34% and 66% were achieved when 5-hydroxymethylfurfural (HMF), fructose, sucrose and inulin were used as starting materials, respectively.
Co-reporter:Bin Zhang, Yulei Zhu, Guoqiang Ding, Hongyan Zheng and Yongwang Li
Green Chemistry 2012 vol. 14(Issue 12) pp:3402-3409
Publication Date(Web):09 Oct 2012
DOI:10.1039/C2GC36270H
The aqueous-phase hydrogenolysis of furfuryl alcohol (FFA) to 1,2-pentanediol (1,2-PeD) was carried out on a series of supported Ru catalysts and MnOx supported Pt, Pd and Rh catalysts. The Ru/MnOx catalysts showed high selectivity for 1,2-PeD, while the Pd and Rh catalysts displayed high selectivity for tetrahydrofurfuryl alcohol. The function of MnOx, the effects of solvent, temperature, H2 pressure and reaction time were further investigated. The support MnOx in the Ru/MnOx catalysts not only suppressed the polymerization of the FFA, but also enhanced the 1,2-PeD selectivity. Low pressure and high temperature favoured the generation of 1,2-PeD, and water significantly enhanced the reaction rate. At 150 °C, 1.5 MPa, the yield of 1,2-PeD was up to 42.1% over the Ru/MnOx catalyst. The proposed mechanism for FFA hydrogenolysis in aqueous medium over the Ru/MnOx catalyst is suggested to occur via a partially hydrogenated intermediate.
Co-reporter:Shanhui Zhu, Yulei Zhu, Shunli Hao, Hongyan Zheng, Tao Mo and Yongwang Li
Green Chemistry 2012 vol. 14(Issue 9) pp:2607-2616
Publication Date(Web):31 Jul 2012
DOI:10.1039/C2GC35564G
The one-step hydrogenolysis of biomass-derived glycerol to propanols (1-propanol + 2-propanol), which are known as biopropanols, was investigated over different supported Pt–H4SiW12O40 (HSiW) bi-functional catalysts in aqueous media. Among the catalysts/supports tested, Pt–HSiW supported over ZrO2 converted glycerol to biopropanols with high selectivity and high yield (94.1%), while exhibiting long-term stability (160 h). In addition, this catalyst can be resistant to the impurities present in crude glycerol. The reaction pathway to propanols from glycerol is proposed to proceed mainly through 1,2-propanediol. With the strategy toward one-step hydrogenolysis of glycerol to biopropanols sustainably, the biomass can be readily transformed to biodiesel and biopropanols via glycerol, which will bring about the benign development of the biodiesel industry.
Co-reporter:Tiansheng Deng, Xiaojing Cui, Yongqin Qi, Yinxiong Wang, Xianglin Hou and Yulei Zhu
Chemical Communications 2012 vol. 48(Issue 44) pp:5494-5496
Publication Date(Web):11 Apr 2012
DOI:10.1039/C2CC00122E
The incompletely coordinated zinc ions in the concentrated aqueous ZnCl2 solution catalyze the direct conversion of carbohydrates into 5-hydroxymethylfurfural, and a moderate HMF yield up to 50% can be achieved.
Co-reporter:Xiaoyuan Liao, Sheng-Guang Wang, Xiaomin Xiang, Yulei Zhu, Xichun She, Yongwang Li
Fuel Processing Technology 2012 Volume 96() pp:74-79
Publication Date(Web):April 2012
DOI:10.1016/j.fuproc.2011.11.025
Three kinds of SO3H-functionalized Brønsted-acidic ionic liquids with different acidities were applied to the etherification of glycerol with tert-butyl alcohol. High conversion and good selectivity were obtained under mild conditions. Among the ionic liquids investigated, those having a HSO4− anion afforded the highest glycerol conversion and those having a F3CSO3− anion afforded the largest head product selectivity for glycerol etherification. The minimum-energy geometries and experimental results show that acidities and catalytic activities of ionic liquids are not only related to their structures but also to their immiscibility.
Co-reporter:Lungang Chen;Hongyan Zheng;Chenghua Zhang;Yongwang Li
Journal of Chemical Technology and Biotechnology 2012 Volume 87( Issue 8) pp:1089-1097
Publication Date(Web):
DOI:10.1002/jctb.3719
Abstract
BACKGROUND: The catalytic degradation of aqueous Fischer–Tropsch (FT) effluents to fuel gas over Ru/AC has been investigated. In order to understand the catalytic performance and stability of oxide-supported Ru catalysts, several oxide supports (titania, zirconia, γ-alumina and silica) were selected for study, with a focus on the hydrothermal stability of catalysts.
RESULTS: The catalytic efficiency for transforming the oxygenates in aqueous FT effluents to C1–C6 alkanes decreased in the order: Ru/ZrO2∼ Ru/TiO2 > Ru/SiO2 > Ru/Al2O3. The conversion of alcohols was greatly suppressed over Ru/γ-Al2O3. The former two catalysts (Ru/ZrO2 and Ru/TiO2) exhibited enhanced efficiency and long-term stability (400 h) relative to Ru/SiO2 and Ru/Al2O3. N2-physisorption, XRD and SEM showed that titania and zirconia exhibited high structural stability in an aqueous environment. However, the structures of γ-alumina and silica were unstable due to significant drop in surface area and adverse changes in surface morphology. Especially for the case of the Ru/γ-Al2O3 catalyst, the γ-alumina was transformed into boehmite structure after reaction, and metal leaching and carbon deposition were extensive.
CONCLUSION: Ru/ZrO2 or Ru/TiO2 may be a promising alternative for degrading aqueous FT effluents due to their long-term stability. Copyright © 2012 Society of Chemical Industry
Co-reporter:Lungang Chen;Hongyan Zheng;Chenghua Zhang;Bin Zhang;Yongwang Li
Journal of Chemical Technology and Biotechnology 2012 Volume 87( Issue 1) pp:112-122
Publication Date(Web):
DOI:10.1002/jctb.2690
Abstract
BACKGROUND: Aqueous phase Fischer–Tropsch (FT) effluents co-produced with hydrocarbons in the FT process contain various water-soluble oxygenates, e.g. carboxylic acids, alcohols. Purification of the FT aqueous phase is important from the viewpoint of effective resource utilization and environmental stewardship. In this work, an aqueous-phase hydrodeoxygenation process was investigated for the degradation of FT aqueous phases.
RESULTS: The Ru/AC catalyst was determined to be the most active catalyst. The key parameters, i.e. temperature, pressure, weight hourly space velocity and Ru loading, were comprehensively optimized. Under optimal conditions, ca 98% of the oxygenates were converted to C1∼C6 alkanes. The degraded water had no odour, a neutral pH, and as low as 1000 mg L−1 chemical oxygen demand. The Ru/AC catalyst exhibited long-term stability (1300 h) and no ruthenium leaching. A reaction pathway is proposed for this process in which the carboxylic acids are hydrogenated to alcohols via the formation of aldehydes. Alcohols and aldehydes are then converted to methane and alkanes of one carbon atom less than the substrate through CC bond cleavage.
CONCLUSIONS: This process is effective for treating FT aqueous phase effluent, and holds great promise for industrial applications due to its high efficiency, simplicity and stability. Copyright © 2011 Society of Chemical Industry
Co-reporter:Shanhui Zhu;Shunli Hao;Lungang Chen;Bin Zhang
Catalysis Letters 2012 Volume 142( Issue 2) pp:267-274
Publication Date(Web):2012 February
DOI:10.1007/s10562-011-0757-1
Hydrogenolysis of glycerol to 1,3-propanediol in aqueous-phase was investigated over Pt-H4SiW12O40/SiO2 bi-functional catalysts with different H4SiW12O40 (HSiW) loading. Among them, Pt-15HSiW/SiO2 showed superior performance due to the good dispersion of Pt and appropriate acidity. It is found that Brønsted acid sites facilitate to produce 1,3-PDO selectively confirmed by Py-IR. The effects of weight hourly space velocity, reaction temperature and hydrogen pressure were also examined. The optimized Pt-HSiW/SiO2 catalyst showed a 31.4% yield of 1,3-propanediol with glycerol conversion of 81.2% at 200 °C and 6 MPa.
Co-reporter:Guoqiang Ding;Hongyan Zheng;Hongmei Chen;Yongwang Li
Journal of Chemical Technology and Biotechnology 2011 Volume 86( Issue 2) pp:231-237
Publication Date(Web):
DOI:10.1002/jctb.2503
Abstract
BACKGROUND: Catalytic upgrading of fermentation-derived succinic acid or its derivates (succinic acid esters and succinic anhydride) to value added chemicals has received great attention recently. The aim of this work is to provide a process for the production of tetrahydrofuran from succinic acid esters.
RESULTS: The hydrogenolysis of biomass-derived diethyl succinate was investigated over CuOZnO and CuOZnO/solid acid (HY, HZSM-5, SAPO-11 and Al2O3) catalysts in a fixed-bed reactor. Over CuOZnO, gamma-butyrolactone and 1,4-butanediol can be selectively produced under appropriate reaction conditions, while the selectivity of tetrahydrofuran is relatively low due to the weak acidity of CuOZnO. Over CuOZnO/HZSM, both the formed 1,4-butanediol and ethanol can be further converted to tetrahydrofuran and diethyl ether, while tetrahydrofuran is selectively produced over CuOZnO/HY. CuOZnO/Al2O3 and CuOZnO/SAPO exhibit slight improvements in terms of selectivity to tetrahydrofuran when compared with CuOZnO.
CONCLUSION: CuOZnO/HY is an appropriate catalyst to produce tetrahydrofuran from biomass-derived diethyl succinate with high activity, selectivity and stability. Furthermore, Brønsted acid sites with appropriate acid strength are responsible for the selective formation of tetrahydrofuran under the applied reaction conditions. Copyright © 2010 Society of Chemical Industry
Co-reporter:Lungang Chen, Yulei Zhu, Hongyan Zheng, Chenghua Zhang, Bin Zhang, Yongwang Li
Journal of Molecular Catalysis A: Chemical 2011 Volume 351() pp:217-227
Publication Date(Web):December 2011
DOI:10.1016/j.molcata.2011.10.015
For the aqueous-phase hydrodeoxygenation (APHDO) of carboxylic acids over the Ru/C, Ru/ZrO2 and Ru/Al2O3 catalysts, the CO hydrogenation and C–C bond cleavage reactions were studied by collecting reaction kinetics data and the measures of DRIFTS. The C–C bond cleavage was improved at high temperature and with high metal loadings. The acidic supports in combination with Ru metal can favor the CO hydrogenation of carboxyl. The C–C bond cleavage derived from the decarbonylation of acyl on the catalyst was studied by the measures of DRIFTS. The APHDO and DRIFTS results demonstrated that the C–C bond cleavage was favored in the order of Ru/C > Ru/ZrO2 > Ru/Al2O3. The catalysts were characterized by multiple methods (H2-TPR, NH3-TPD, CO-FTIR and DRIFTS of propanoic acid). It is concluded that the effect of support on the reaction routes may be attributed to these factors of catalysts, i.e., surface acidity, metal–support interaction and electronic state of Ru species.Graphical abstractThe hydrodeoxygenation routes of carboxylic acids over the supported Ru catalysts was elucidated: the CO hydrogenation of acyl intermediate gives the production of alcohol, the C–C bond cleavage gives the adsorbed CO and hydrocarbon moieties by the decarbonylation of acyl intermediate, and then the adsorbed CO and hydrocarbon moieties hydrogenate to methane and Cn−1-alkane.Highlights► The APHDO of carboxylic acids was studied over the supported Ru catalysts. ► The C–C bond cleavage reaction is derived from the decarbonylation of acyl. ► The C–C bond cleavage reaction is dominant over the Ru/ZrO2 at high temperature. ► The C–C bond cleavage reaction is greatly inhibited over the Ru/Al2O3. ► The C–C bond cleavage or CO hydrogenation strongly depends on the nature of support.
Co-reporter:Wei Zhang, Yulei Zhu, Shasha Niu, Yongwang Li
Journal of Molecular Catalysis A: Chemical 2011 Volume 335(1–2) pp:71-81
Publication Date(Web):1 February 2011
DOI:10.1016/j.molcata.2010.11.016
Vapor-phase decarbonylation of furfural to furan was performed on K-doped Pd/Al2O3 catalysts in a fixed-bed reactor. A series of K-doped catalysts were prepared by impregnation method with various potassium salt precursors and different potassium content. The catalyst evaluation results revealed that the doping of K not only promoted the furfural decarbonylation, but also suppressed the hydrogenation side reaction. Among the investigated catalysts, Pd–K2CO3/Al2O3 (K% = 8 wt.%) presented the best performance and achieved the furan yields up to 99.5% at 260 °C. The selectivity of 2-methylfuran would approach zero at high K content (K% > 4 wt.%). Furthermore, the catalysts were characterized by BET, SEM, ICP, H2-TPR, H2-TPD, H2-chemisorption, CO-FTIR, furfural-TPSR, and furfural-FTIR experiments. It was shown that the dopant phase had a remarkable effect on the precursor Pd2+ and the reduced Pd metal particles. Furfural-TPSR and furfural-FTIR exhibited that K-doped catalysts enhanced the furfural adsorption and promoted the decarbonylation reaction, which was due to the different adsorption mode and intensity of furfural on K-doped and undoped samples. Besides, the decrease of C–O adsorption of furfural (η2(C,O)-furfural) by K doping is the main reason for suppressing the furfural hydrogenation.Graphical abstractThe furfural-TPSR results exhibit that furan desorption temperature is decreased on K-doped Pd catalysts, which illustrates that K can promote furfural decarbonylation on Pd catalyst.Research highlights▶ The yield of furan is 99.5% at 260 °C on Pd–K2CO3/Al2O3 (K% = 8 wt.%) catalyst. ▶ The selectivity of 2-methylfuran will be zero at higher K-content catalysts. ▶ Furfural-TPSR indicates that K-doped catalysts promote furfural decarbonylation. ▶ Furfural-FTIR shows that K-doped catalysts change the adsorption mode of furfural. ▶ The decrease of η2(C,O)-furfural by K-doping inhibits furfural hydrogenation.
Co-reporter:Xiaoyuan Liao, Yulei Zhu, Sheng-Guang Wang, Yongwang Li
Fuel Processing Technology 2009 Volume 90(7–8) pp:988-993
Publication Date(Web):July–August 2009
DOI:10.1016/j.fuproc.2009.03.015
A two-step method is proposed to obtain high selectivity and high conversion rate for producing additive triacetylglycerol of biofuel from its byproduct glycerol. The esterification of glycerol with acetic acid was carried out over resin and zeolites. Amberlyst-35 was found to be an excellent catalyst. The reaction conditions were optimized by testing catalysts, temperatures, feedstock ratios as well as loads of catalysts. The optimal conditions are temperature of 105 °C and an acetic acid to glycerol molar ratio of 9:1 with 0.5 g catalyst. After the 4 hour reaction of the optimal condition, the selectivity of triacetylglycerol reaches almost 100% in 15 min by adding thereto acid anhydride. Recycling experiments indicate that no significant deactivation of Amerlyst-35 occurred during the reaction.
Co-reporter:Long Huang;Yu-Lei Zhu;Hong-Yan Zheng;Yong-Wang Li;Zhi-Yong Zeng
Journal of Chemical Technology and Biotechnology 2008 Volume 83( Issue 12) pp:1670-1675
Publication Date(Web):
DOI:10.1002/jctb.1982
Abstract
BACKGROUND: The conversion of glycerol to value-added derivatives is now critical, owing to the large surplus of glycerol from biodiesel production. The main objective of this work is to develop a novel process for converting solvent-free glycerol to 1,2-propanediol.
RESULTS: Several catalysts were screened for aqueous-phase hydrogenolysis of glycerol in an autoclave. The most effective catalysts (Ni/Al2O3, Cu/ZnO/Al2O3) were further tested for vapor phase hydrogenolysis in a fixed-bed. Ni/Al2O3 did not prove as effective for the production of 1,2-propanediol because of the high selectivity to CH4 and CO. Over Cu/ZnO/Al2O3, glycerol was mainly converted to the desired 1,2-propanediol and the reaction intermediate acetol. The production of 1,2-propanediol was favoured at higher hydrogen pressure. At 190 °C and 0.64 MPa, near complete conversion of glycerol was achieved with 1,2-propanediol selectivity up to 92%. In addition, a higher concentration (between 43.4% and 0.8%) of acetol was detected and an approximately stoichiometric relationship was found between acetol and 1,2-propanediol.
CONCLUSION: 1,2-propanediol can be produced with high yields via the vapor phase hydrogenolysis of glycerol over Cu/ZnO/Al2O3. Furthermore, the mechanism of 1,2-propanediol formation is suggested to proceed mainly through an acetol route over Cu/ZnO/Al2O3. Copyright © 2008 Society of Chemical Industry
Co-reporter:Long Huang, Yulei Zhu, Chunfang Huo, Hongyan Zheng, Gang Feng, Chenghua Zhang, Yongwang Li
Journal of Molecular Catalysis A: Chemical 2008 Volume 288(1–2) pp:109-115
Publication Date(Web):3 June 2008
DOI:10.1016/j.molcata.2008.03.026
The catalytic transfer hydrogenation (CTH) between alcohol and alkene was investigated over Cu/Al2O3 catalyst via mechanical mixture of the supported catalyst and the pure support. It is found that the CTH activities are highly depended on the amount and acid/basic properties of the mechanically mixed support, clearly indicating the assistant role of support. In addition, only alkene with high activity of hydrogenation can really act as hydrogen acceptor. Based on these, a new bifunctional reaction pathway is proposed. Alcohol dehydrogenates to form alkoxide on Al2O3 surface (R1CH(OH)R2 → R1CH(O)R2 + H), and H atom migrates to the metallic Cu patches via reverse hydrogen spillover, while extraction of α-hydrogen forming ketone (R1CH(O)R2 → R1C(O)R2 + H) occurs on Cu or Cu–Al2O3 interface. On the metallic Cu patches, alkene hydrogenates yielding alkane (R3CH = CHR4 + 2H → R3CH2CH2R4). This mechanism can give a better explanation for the observed acceleration or deceleration role of hydrogen acceptor to alcohol dehydrogenation.By the means of mechanical mixture of supported catalyst and its pure support, the support is demonstrated to play a remarkable assistant role in heterogeneous catalytic transfer hydrogenation between alkene and alcohol over Cu/Al2O3. The reaction results strongly suggest a bifunctional mechanism as follows: (Step 1) alcohols absorption, (Step 2) alcohols dehydrogenation with cooperation of Al2O3 and Cu, (Step 3) reverse hydrogen spillover from Al2O3 surface to metal phase, (Step 4) the alkene hydrogenation on metal phase.
Co-reporter:Hong-Yan Zheng, Yu-Lei Zhu, Zong-Qing Bai, Long Huang, Hong-Wei Xiang and Yong-Wang Li
Green Chemistry 2006 vol. 8(Issue 1) pp:107-109
Publication Date(Web):17 Nov 2005
DOI:10.1039/B513584B
A novel process involving the coupling of the dehydrogenation of cyclohexanol and the hydrogenation of furfural has been studied for the synthesis of cyclohexanone and 2-methylfuran over the same Cu–Zn–Al catalyst, realizing good energy efficiency, optimal hydrogen ultilization, and environmentally benign process.
Co-reporter:Shanhui Zhu, Xiaoqing Gao, Fang Dong, Yulei Zhu, Hongyan Zheng, Yongwang Li
Journal of Catalysis (October 2013) Volume 306() pp:155-163
Publication Date(Web):1 October 2013
DOI:10.1016/j.jcat.2013.06.026
•Ag1PW presented the best activity for glycerol esterification with acetic acid.•The TON of Ag1PW was up to 2189.9 h−1.•Ag-exchanged HPW exhibited outstanding water-tolerant property.•A mechanistic scheme for glycerol esterification with acetic acid was proposed.•Ag1PW catalyst did not suffer from deactivation in five consecutive reaction tests.A series of highly active, selective, and stable silver-exchanged phosphotungstic acid (AgPW) catalysts were prepared, characterized, and evaluated for bio-derived glycerol esterification with acetic acid to produce valuable biofuel additives. The structures, morphologies, acidities, and water tolerance of these samples were determined by FTIR, Raman, XRD, SEM-EDX, FT-IR of pyridine adsorption, and H2O-TPD. Several typical acidic catalysts were also performed for comparison. Among them, partially silver-exchanged phosphotungstic acid (Ag1PW) presented exceptionally high activity, with 96.8% conversion within just 15 min of reaction time and remarkable stability, due to the unique Keggin structure, high acidity as well as outstanding water-tolerance property. A plausible reaction mechanism was also proposed. In addition, this Ag1PW catalyst exhibited universal significance for esterification, holding great potential for a wide range of other acid-catalyzed reactions.Partially silver-exchanged phosphotungstic acid (Ag1PW) presented exceptionally high activity for glycerol esterification with acetic acid to produce valuable biofuel additives, with 96.8% conversion even just 15 min. The TON of Ag1PW is up to 2189.9 h−1, which is the best catalytic activity ever reported for glycerol esterification.Download high-res image (151KB)Download full-size image
Co-reporter:Hongmei Chen, Jingjing Tan, Jinglei Cui, Xiaohai Yang, Hongyan Zheng, Yulei Zhu, Yongwang Li
Molecular Catalysis (May 2017) Volume 433() pp:346-353
Publication Date(Web):1 May 2017
DOI:10.1016/j.mcat.2017.02.039
•96.1% yield to MG was achieved over Ag-B2O3/SiO2 under 180 °C and 0.5 MPa H2.•Addition of B2O3 can promote the dispersion and stability of Ag NPs on SiO2 support.•Addition of B2O3 favors the formation of Ag centers with electron-deficient state.•The strong interaction between Ag and boron promotes the activity of the catalysts.A highly active and stable catalyst for the hydrogenation of dimethyl oxalate (DMO) to methyl glycolate (MG) had been developed. The Ag-B2O3/SiO2 catalysts were prepared by impregnation method with boric acid (H3BO3). The properties and the structures of the catalysts were fully characterized by BET, XRD, H2-TPR, NH3-TPD, FTIR, XPS and TEM. Compared with Ag/SiO2 catalyst, the Ag-B2O3/SiO2 catalyst exhibited significantly enhanced catalytic performance and high stability for the hydrogenation of DMO to MG under relatively milder reaction conditions (180 °C, 0.5 MPa). A high yield of 96.1% for MG was achieved over Ag-B2O3/SiO2 catalyst, while the yield of MG was only 54.3% over Ag/SiO2 catalyst. The excellent catalytic performance for Ag-B2O3/SiO2 catalyst was attributed to the introduction of B2O3. The addition of B2O3 to Ag/SiO2 catalyst favored the formation of highly dispersed Ag centers with electron-deficient state, which can strongly bind and activate the ester and acyl groups of DMO in the hydrogenation processes. Besides its effectiveness, the catalyst showed an excellent stability which can be performed for 264 h under the reaction conditions of 180 °C, 0.5 MPa H2 and the weight space velocity of 0.2 h−1.Doping B2O3 to an Ag/SiO2 catalyst notably improves its activity as well as its stability for the vapor-phase hydrogenation of dimethyl oxalate (DMO) to methyl glycolate (MG).Download full-size image
Co-reporter:Qingwei Meng, Chengwu Qiu, Hongyan Zheng, Xianqing Li, Yulei Zhu, Yongwang Li
Molecular Catalysis (May 2017) Volume 433() pp:111-121
Publication Date(Web):1 May 2017
DOI:10.1016/j.mcat.2017.02.035
•Highly dispersed Pd/Al2O3 was prepared based on electrostatic attraction strategy.•Action mechanism of pH of impregnation solution was explored.•Catalysts with small Pd nanoparticles showed superior catalytic performance.•Structure sensitive behavior of catalysts was discussed.•Surface properties of catalysts were characterized by in situ FTIR.Decarbonylation of 5-hydroxymethylfurfural (HMF) provides a potential way to utilize the abundant natural hexoses derived from cellulose or hemicellulose. Herein, we propose for the first time that a Pd/Al2O3 prepared based on an electrostatic attraction strategy can efficiently convert HMF into furfuryl alcohol (FOL). Ammonia solution with high pH value could realize the electrostatic attraction assumption in the interface of support and palladium complex, while diluted hydrochloric acid with low pH value could cause the instability of H+ ions on Al2O3 surface, leading to larger Pd nanoparticles (NPs) of the catalyst and lowering the decarbonylation activity. A structure-sensitive behavior was discussed that the intrinsic activity of catalyst rised with the decreased size of Pd NPs, which could be illustrated by that the smaller particles exposed more defective Pd sites, on which the decarbonylation adsorption mode of η2(C, O) was preferred. FOL yield of 95% was obtained through modulation of reaction conditions.Download full-size image
Co-reporter:Shanhui Zhu, Xiaoqing Gao, Yulei Zhu, Yifeng Zhu, Hongyan Zheng, Yongwang Li
Journal of Catalysis (July 2013) Volume 303() pp:70-79
Publication Date(Web):1 July 2013
DOI:10.1016/j.jcat.2013.03.018
•B2O3 can promote the dispersion of copper species and stabilize copper particles.•Addition of B2O3 to Cu/SiO2 greatly enhanced activity and stability.•100% Conversion and 98.0% 1,2-propanediol selectivity were achieved over 3CuB/SiO2.•1,2-Propanediol yield was proportional to Cu specific surface area.•Glycerol hydrogenolysis is a structure-sensitive reaction.Cu/SiO2 catalyst has been extensively applied in glycerol hydrogenolysis for its high selectivity to 1,2-propanediol, while suffering from severe deactivation easily. B2O3 is frequently used as an additive for stabilizing active species. Thus, a series of Cu/SiO2 catalysts with various B2O3 loadings for glycerol hydrogenolysis were prepared via precipitation-gel method followed by impregnation with boric acid. These catalysts were fully characterized by ICP, BET, XRD (in situ XRD), N2O chemisorption, H2-TPR, NH3-TPD, IR, Raman, XPS, and TEM. Addition of B2O3 to Cu/SiO2 can greatly restrain the growth of copper particles and promote the dispersion of copper species upon calcination, reduction and reaction, which resulted in the enhanced catalytic activity and stability. The optimal 3CuB/SiO2 reached complete conversion with 98.0% 1,2-propanediol selectivity. The strong correlation between 1,2-propanediol yield and Cu surface area gave direct evidence that the active Cu species were the primary active sites for glycerol hydrogenolysis.Doping B2O3 to Cu/SiO2 catalyst significantly improved activity and long-term performance for glycerol hydrogenolysis to 1,2-propanediol. The strong correlation between 1,2-propanediol yield and Cu surface area gave direct evidence that Cu surface area was a key parameter for developing fundamental mechanistic insight into the performance of glycerol hydrogenolysis over Cu-based catalyst.Download high-res image (126KB)Download full-size image
Co-reporter:Xiaomin Xiang, Bin Zhang, Guoqiang Ding, Jinglei Cui, Hongyan Zheng, Yulei Zhu
Catalysis Communications (5 November 2016) Volume 86() pp:41-45
Publication Date(Web):5 November 2016
DOI:10.1016/j.catcom.2016.08.013
•2-formyloxyfuran is a crucial reaction intermediate.•Mg2 + ions suppress the oxidation of furan ring and promote oxidation of HCO.•Mg2 + ions contact with HCO of furfural promoted the HOO attacking HCO.•The bases can promote the ionization of H2O2 to HOO– species.•High selectivities of 2(5H)-furanone (44.8%) and succinic acid (38.0%) are obtained.The oxidation of furfural in H2O2 and H2O2–Mg(OH)2 system were systematically investigated and a rational explanation for the reaction mechanism was proposed. 2-formyloxyfuran, from selective oxidation of HCO group in furfural, was a crucial intermediate. The addition of Mg(OH)2 suppressed the oxidation of furan ring of furfural and enhanced selectivities of 2(5H)-furanone (44.8%) and succinic acid (38.0%). FT-IR, Gaussian calculation and experimental results indicated that the process of furfural oxidation with H2O2 is homogeneous, and the synergy between dissolved Mg2 + cations and OH− ions facilitates the HOO− attacking the carbon atom of HCO other than the CC bound of furan ring.Download high-res image (108KB)Download full-size image
Co-reporter:Hongmei Chen, Jingjing Tan, Yulei Zhu, Yongwang Li
Catalysis Communications (5 January 2016) Volume 73() pp:46-49
Publication Date(Web):5 January 2016
DOI:10.1016/j.catcom.2015.10.010
•An effective Ni2P/TiO2 catalyst was proposed for dimethyl oxalate hydrogenation.•A 93.0% conversion of dimethyl oxalate was obtained under 210 °C.•A selectivity of 88.0% to methyl glycolate was achieved under 210 °C.•Ni2P/TiO2 catalyst showed a superior stability which can be performed for 3600 h.An effective and stable bifunctional Ni2P/TiO2 catalyst was proposed for gas-phase hydrogenation of dimethyl oxalate to corresponding alcohols. A 93.0% conversion of DMO with a selectivity of 88.0% to methyl glycolate was observed under 210 °C. Moreover, the catalyst showed an excellent stability which can be performed for 3600 h under the reaction conditions of 230 °C, 3 MPa H2 and the weight space velocity of 0.1 h− 1.An effective and stable Ni2P/TiO2 catalyst for the hydrogenation of dimethyl oxalate to methyl glycolate with an excellent stability (3600 h) was proposed.Download high-res image (121KB)Download full-size image
Co-reporter:Long Huang, Yulei Zhu, Hongyan Zheng, Mingxian Du, Yongwang Li
Applied Catalysis A: General (31 October 2008) Volume 349(Issues 1–2) pp:
Publication Date(Web):31 October 2008
DOI:10.1016/j.apcata.2008.07.031
Vapor-phase hydrogenolysis of ethyl lactate to 1,2-propanediol was performed over a series of SiO2 supported metal (Fe, Co, Ni, Ru, and Pd) catalysts in a fixed-bed reactor. Among them, the Co/SiO2 and Cu/SiO2 catalysts exhibit promising performance, and the Co/SiO2 were more active than the traditional copper catalysts under mild conditions. Effects of support, metal loading and preparation method were investigated to optimize the performance of the Co-based catalysts. Over the optimal catalyst (a 10 wt.% Co/SiO2 catalyst prepared via rotary evaporation drying method), the 1,2-propanediol selectivity was in excess of 98% at 90.2% lactate conversion, 2.5 MPa and 160 °C. The cobalt catalysts were characterized by X-ray diffraction (XRD) and temperature programmed reduction by H2 (H2-TPR) and temperature programmed desorption of H2 (H2-TPD). Interestingly, a quasi-linear correlation is observed between the average reaction rate and the percentage of bulk-like Co3O4 phase precursors, suggesting that the metallic cobalt from the bulk-like Co3O4 phase precursor is more active than that from the cobalt surface support species. The emerging technologies for production of low-cost lactate ester, make this high-yield route a sustainable benign process for 1,2-propanediol.The SiO2 supported cobalt catalysts are active for vapor-phase hydrogenolysis of ethyl lactate to 1,2-propanediol at mild conditions. Interestingly, a quasi-linear correlation is observed between average reaction rate and the percentage of the bulk-like Co3O4 phase precursors, suggesting that the metallic cobalt from the bulk-like Co3O4 phase precursor is more active.
Co-reporter:Bin Zhang, Guoqiang Ding, Hongyan Zheng, Yulei Zhu
Applied Catalysis B: Environmental (15 May 2016) Volume 185() pp:380
Publication Date(Web):15 May 2016
DOI:10.1016/j.apcatb.2015.12.029
Co-reporter:Xiaoyuan Liao, Yulei Zhu, Sheng-Guang Wang, Hongmei Chen, Yongwang Li
Applied Catalysis B: Environmental (1 February 2010) Volume 94(Issues 1–2) pp:64-70
Publication Date(Web):1 February 2010
DOI:10.1016/j.apcatb.2009.10.021
Co-reporter:Yifeng Zhu, Xiao Kong, Hongyan Zheng, Guoqiang Ding, Yulei Zhu and Yong-Wang Li
Catalysis Science & Technology (2011-Present) 2015 - vol. 5(Issue 8) pp:NaN4217-4217
Publication Date(Web):2015/06/18
DOI:10.1039/C5CY00700C
Selective conversion of 5-hydroxymethylfurfural (HMF) can produce sustainable fuels and chemicals. Herein, Cu–ZnO catalysts derived from minerals (malachite, rosasite and aurichalcite) were employed for selective hydrogenation of HMF for the first time. High yields of 2,5-dihydroxymethylfuran (~99.1%) and 2,5-dimethylfuran (~91.8%) were obtained tunably over the catalyst with a Cu/Zn molar ratio of 2, due to the well-dispersed metal sites tailored by mineral precursors, well-controlled surface sites and optimized reaction conditions. The relationship between catalytic performance and catalyst properties was elucidated by characterization based on the composition and the structural and surface properties, and catalytic tests. The catalyst can also be extended to selective hydrogenation of other bio-derived molecules (furfural and 5-methylfurfural) to target products. The construction of mineral-derived Cu–ZnO catalysts and the revelation of the structure–performance relationship can be applied to further rational design and functionalization of non-noble Cu catalysts for selective conversion of bio-derived compounds.
Co-reporter:Jingjing Tan, Jinglei Cui, Guoqiang Ding, Tiansheng Deng, Yulei Zhu and Yong-wang Li
Catalysis Science & Technology (2011-Present) 2016 - vol. 6(Issue 5) pp:NaN1475-1475
Publication Date(Web):2015/09/25
DOI:10.1039/C5CY01374G
Efficient aqueous hydrogenation of levulinic acid over supported catalysts is of fundamental and industrial interest but is highly challenging. For Ru/γ-Al2O3 catalysts, the primary problems are low activity and stability that arose from the inhomogeneous dispersion of Ru and the unstable nature of γ-Al2O3 in water. In this work, an integrated strategy was proposed for developing a highly active and stable catalyst for aqueous hydrogenation of LA to GVL. By modification with 3-aminopropyltriethoxysilane (KH550), the abundant surface Al–OH groups of γ-Al2O3 were transformed into a stable Al–O–Si structure, while ruthenium active centres were bonded to a γ-Al2O3 surface via coordination with amino ligands of KH550. This modification favours the formation of highly dispersed Ru centres with an electron-rich state, leading to a superior activity at temperatures as low as 25 °C (GVL yield of 99.1%, TOF of 306 h−1) and high stability.
Co-reporter:Tiansheng Deng, Xiaojing Cui, Yongqin Qi, Yinxiong Wang, Xianglin Hou and Yulei Zhu
Chemical Communications 2012 - vol. 48(Issue 44) pp:NaN5496-5496
Publication Date(Web):2012/04/11
DOI:10.1039/C2CC00122E
The incompletely coordinated zinc ions in the concentrated aqueous ZnCl2 solution catalyze the direct conversion of carbohydrates into 5-hydroxymethylfurfural, and a moderate HMF yield up to 50% can be achieved.
Co-reporter:Qingwei Meng, Chengwu Qiu, Guoqiang Ding, Jinglei Cui, Yulei Zhu and Yongwang Li
Catalysis Science & Technology (2011-Present) 2016 - vol. 6(Issue 12) pp:NaN4388-4388
Publication Date(Web):2016/02/02
DOI:10.1039/C5CY02248G
A series of Pd/Al2O3 catalysts with different alkali earth metals (Mg, Ca, Sr, Ba) and varying Sr loadings (1.8, 3.5, 5.3, 7 and 8.8 wt%) were investigated for 5-hydroxymethylfurfural (HMF) decarbonylation. The alkali earth metal and content were demonstrated to have profound influences on the metal dispersion, electron density of the metal, acid–base properties of the catalyst, and catalytic performance. The Pd3Sr/Al2O3 catalyst exhibited the highest initial activity and furfuryl alcohol selectivity, achieving a yield of 92%. The key to high decarbonylation selectivity is the suppression of hydrogenolysis and etherification side reactions through the attenuation of the acidity of catalysts. Successful catalytic activity not only lies in the increased metallic surface area, but is also affected by the adsorption properties of the carbonyl group and the poisoning CO produced. The catalytic activity is linearly correlated to the surface metallic area at low modifier loading over PdM/Al2O3 catalysts. But along with further increased metallic surface area over PdXSr/Al2O3, HMF conversion initially increased, reaching a plateau over Pd3Sr/Al2O3 and then decreased with increasing Sr loading. A synergistic effect between the Sr species and metallic Pd was proposed, which promoted the migration of carbonyl adsorption from the support to the surface Pd through the electron donation of Sr species to Al2O3 and metallic Pd.
Co-reporter:Fang Dong, Guoqiang Ding, Hongyan Zheng, Xiaoming Xiang, Linfeng Chen, Yulei Zhu and Yongwang Li
Catalysis Science & Technology (2011-Present) 2016 - vol. 6(Issue 3) pp:NaN779-779
Publication Date(Web):2015/08/20
DOI:10.1039/C5CY00857C
Cu/SiO2 catalysts were synthesized by different methods, which greatly influenced their texture and the catalytic performance. The AE-Cu/SiO2 catalyst was prepared via the ammonia evaporation method and showed a 95.5% yield for 2-methylfuran (a promising fuel additive) because of the cooperative effects of surface Cu0, Cu+ species and acid sites, which respectively stemmed from the reduction of highly dispersed CuO species, copper species that fiercely interacted with the support SiO2, and the special structure. The ammonia evaporation method favored the formation of a copper phyllosilicate phase with a lamellar structure, which could provide a large number of Cu nanoparticles and acid sites and further improve the activity and selectivity. Crucially, the stability of the AE-Cu/SiO2 catalyst (>210 h) was also significantly improved due to the enhanced copper–silicon interactions, which could immobilize copper particles and resist the fast transmigration (aggregation and loss) of copper particles in the thermal treatment process. In contrast, the CP-Cu/SiO2 catalyst was synthesized via the conventional precipitation method and presented poor activity and stability toward 2-methylfuran because of large copper particles, severe aggregation and a loss of copper species during reaction. Compared with the conventional CP-Cu/SiO2 catalyst, the use of the AE-Cu/SiO2 catalyst in the synthesis of the biofuel 2-methylfuran could not only improve the yield of the desired product, but also decrease by at least 20 °C the reaction temperature which is propitious for prolonging the lifetime of the Cu/SiO2 catalyst.
Co-reporter:Shanhui Zhu, Xiaoqing Gao, Yulei Zhu, Weibin Fan, Jianguo Wang and Yongwang Li
Catalysis Science & Technology (2011-Present) 2015 - vol. 5(Issue 2) pp:NaN1180-1180
Publication Date(Web):2014/10/30
DOI:10.1039/C4CY01148A
A highly efficient and robust Cu/SiO2 catalyst from a pure-phase copper phyllosilicate precursor was successfully fabricated by the ammonia evaporation hydrothermal (AEH) method. The impregnation (IM) Cu/SiO2 catalyst was prepared for comparison. The structure, morphologies, thermal stability and surface chemical state of these catalysts were comprehensively characterized by ICP, BET, XRD (in situ XRD), N2O chemisorption, H2-TPR, IR and Raman spectroscopy, TEM and XPS. Compared to the IM sample, the AEH catalyst was exceedingly highly active and stable (300 h) for glycerol hydrogenolysis to 1,2-propanediol. The unprecedented catalytic performance was attributed to the strong interaction between Cu and SiO2 species derived from copper phyllosilicate, well-dispersed Cu nanoparticles and the cooperative effect of Cu0 and Cu+. Moreover, active Cu0 species were identified as the primary active sites for glycerol hydrogenolysis, as corroborated by the strong correlation between 1,2-propanediol yield and Cu surface area.
Co-reporter:Fang Dong, Yulei Zhu, Haijun Zhao and Zhicheng Tang
Catalysis Science & Technology (2011-Present) 2017 - vol. 7(Issue 9) pp:NaN1891-1891
Publication Date(Web):2017/03/29
DOI:10.1039/C7CY00233E
The design and development of heterogeneous catalysts is very critical for the synthesis of various chemicals and fuels derived from superfluous biomass. The synthesis of biofuel 2-methylfuran typically derives from the conversion of the formyl group of biomass-derived furfural, because this process is very valuable in terms of the amelioration and remission of the environment and energy crisis. Herein, we designed a series of bifunctional catalysts formed in line with the spatial restriction strategy by anchoring copper nanoparticles (Cu NPs) on phyllosilicate-like structures to enhance copper dispersion and provide properly assembled Lewis acid sites to promote the hydrogenation and hydrogenolysis of the formyl group in furfural, and first applied them to the conversion of the formyl group with high efficiency. However, the modulation of the Cu–Si molar ratio is extremely critical to the possible reduction of metal consumption, full exploitation of the prerequisite metal sites and great improvement of activity. In this work, the catalyst with a Cu–Si molar ratio (actual value = 0.33) lower than that of the industrial catalyst (theoretical value = 1.0) exhibited higher yields of the intermediate furfuryl alcohol (yield = 83.4%) and the desired product 2-methylfuran (yield = 95.5%). More importantly, with the continuous increase of the Cu–Si molar ratio, it is discovered that Cu dispersion regularly decreased and the size of the Cu NPs sequentially increased, and the change of assembled Lewis acid sites surprisingly kept pace with the integrity of the layered structure, as revealed by a series of detailed characterization studies.
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