Zi-feng Yan

•ZnO-Al2O3 mixed oxides were synthesized using a freeze drying modified cation-anion double hydrolysis method•Freeze dried adsorbents exhibited a superior performance in reactive adsorption desulfurization•A large amount of small sized ZnO gives rise to a large sulfur capacity•The absence of the inactive NiAl2O4 phase in the adsorbents allows the fast cleavage of C-S bond in thiophene•High surface area and large pore volume facilitate the mass transfer of reactants and accommodate more sulfurReactive adsorption desulfurization (RADS) is an effective approach to the ultra-deep desulfurization under mild conditions. The sulfur adsorption capacity of the adsorbents strongly depends on the pore structure, the chemical states and the dispersion of active species. In this work, ZnO-Al2O3 mixed oxides with an improved structure were synthesized via a freeze-drying modified cation-anion double hydrolysis (CADH) technique and used as the support. The fresh and spent catalysts were characterized through N2 adsorption-desorption, H2-temperature programmed reduction, X-ray diffraction, UV–vis diffuse reflection spectroscopy, Fourier transformed infrared spectroscopy and transmission electron microscopy (TEM). Freeze drying technique provided the adsorbent with a smaller sized ZnO and an improved pore structure compared with the normal oven drying method. Evaluation results in the RADS of a high sulfur model gasoline reveals that the freeze-dried Ni/ZnO-Al2O3 (40 °C) with a crystallization temperature of 40 °C exhibits a superior RADS performance with an accumulative sulfur adsorption capacity of 90 mg S/g, which is 5.3% and 118% higher than those of adsorbents prepared by the normal oven drying and the conventional kneading methods. A high amount of small ZnO particles, improved textural properties and the absence of inactive NiAl2O4 phase are among the factors accounting for the superior RADS performance of Ni/ZnO-Al2O3 adsorbent prepared by the freeze-drying method. Upon four RADS-regeneration cycles, sample Ni/ZnO-Al2O3 (40°C) exhibited a high stability without evident activity loss.

Cation–anion double hydrolysis derived mesoporous mixed oxides for reactive adsorption desulfurization

Co-reporter:Rooh Ullah, Peng Bai, Pingping Wu, Bowen Liu, Fazle Subhan, Zifeng Yan

Microporous and Mesoporous Materials 2017 Volume 238() pp:36-45

Publication Date(Web):15 January 2017

DOI:10.1016/j.micromeso.2016.02.037

•ZnO–Al2O3 mixed oxides were synthesized using a cation–anion double hydrolysis method.•Mixed oxide based adsorbents exhibited high activity and large sulfur capacity in reactive adsorption desulfurization.•The absence of the inactive NiAl2O4 phase in the adsorbents allowed the fast cleavage of C–S bond in thiophene.•The high concentration of surface Lewis acid sites in mixed oxides favored the adsorption of thiophene.•The high dispersion of ZnO in mixed oxides led to high diffusion rate of sulfur in ZnO particles.Mesoporous ZnO–Al2O3 mixed oxides (MO) were synthesized by double hydrolysis method at different temperatures and used as the support for the preparation of Ni/MO adsorbents. The reactive adsorption desulfurization (RADS) performance of adsorbents was evaluated in a fixed bed microreactor using thiophene as a model compound. The adsorbents before and after RADS were characterized by X-ray diffraction, N2 adsorption/desorption, thermogravimetric analysis, Fourier transformed infrared spectrometry and transmission electron microscopy techniques. Results show that Ni/MO samples exhibited much higher RADS activity and larger accumulative sulfur capacity than sample NZA-K prepared using the conventional kneading method. The desulfurization activity of Ni/MO adsorbents decreased with increasing the crystallization temperature of MO. As a result, sample Ni/ZnO–Al2O3-60 °C synthesized at 60 °C showed the best desulfurization performance among all Ni/MO adsorbents. Detailed characterization results revealed that the high dispersion of NiO and ZnO, the absence of inactive NiAl2O4 and high concentration of surface Lewis acid sites may account for the superior RADS performance of Ni/MOs samples. Furthermore, based on the experimental results, a mechanism is proposed for the RADS process with Ni/MO adsorbents.

Layered double hydroxides toward high-performance supercapacitors

Co-reporter:Xuejin Li;Dongfeng Du;Yu Zhang;Wei Xing;Qingzhong Xue;Zifeng Yan

Journal of Materials Chemistry A 2017 vol. 5(Issue 30) pp:15460-15485

Publication Date(Web):2017/08/01

DOI:10.1039/C7TA04001F

The urgent demand for clean energies and rapid development of modern electronic technologies have led to enthusiastic research on novel energy storage technologies, especially for supercapacitors. The most important part is designing electrode materials with excellent capacitive performance. Layered double hydroxides (LDHs) have sparked intense interest among researchers in the past decade due to the facile tunability of their composition, structure and morphology. Various and fruitful accomplishments have been achieved toward developing LDH-based materials for supercapacitor electrodes. This review outlines the recent advances in the designing of LDH-based electrode materials for supercapacitors. Feasible and practical strategies for improving the capacitive performance of LDH-based materials have been discussed and highlighted in terms of tuning the composition of LDHs, designing the electrode structure and assembling applicable supercapacitor devices. Through the ceaseless efforts of scientists, the capacitive performance and practicability of LDH-based materials have been greatly ameliorated, making them more competitive for modern energy storage applications.

In situ one-step synthesis of Fe3O4@MIL-100(Fe) core-shells for adsorption of methylene blue from water

Co-reporter:Sobia Aslam, Jingbin Zeng, Fazle Subhan, Min Li, Fenglei Lyu, Yanpeng Li, Zifeng Yan

Journal of Colloid and Interface Science 2017 Volume 505(Volume 505) pp:

Publication Date(Web):1 November 2017

DOI:10.1016/j.jcis.2017.05.090

A new route for Fe3O4@MIL-100(Fe) core-shells is proposed via in situ one-step hydrothermal strategy, in which Fe3O4 microspheres not only serve as magnetic cores but also provide Fe(III) for MIL-100(Fe) synthesis. The MIL-100(Fe) is uniformly grown as a shell on the surface of Fe3O4, and the shell thickness can be fine-tuned from 73.5 to 148 nm by simply controlling the reaction time. Compared with Fe3O4, the surface area and pore volume of the Fe3O4@MIL-100(Fe) are significantly increased while the magnetism is barely affected. The application of Fe3O4@MIL-100(Fe) in adsorption was tested using several dyes as model analytes, and showed high adsorption capacity (221 mg g−1) towards methylene blue (MB), which is based on electrostatic interactions and size filter effect. The MB adsorption isotherm follows Langmuir model and pseudo second-order kinetic model. Intra-particle diffusion model reveals that both film and pore diffusions are involved in the rate limiting steps. The adsorption is controlled by enthalpy change rather than entropy effect. ΔH, ΔS and ΔG values indicated that the adsorption process was spontaneous and exothermic. Simple synthesis procedure, immense magnetism, high adsorption capacity and excellent reusability of Fe3O4@MIL-100(Fe) make it an attractive candidate for application of MB removal from polluted environmental samples.In situ one-step hydrothermal strategy for synthesis of Fe3O4@MIL-100(Fe) core-shell magnetic microspheres and used for adsorptive removal of MB dye from aqueous solution.Download high-res image (190KB)Download full-size image

Remarkably high performance of clew-like ZnO superstructure in reactive adsorption desulfurization

Co-reporter:Peng Bai 白鹏;Bowen Liu 刘博文;Pingping Wu 吴萍萍;Rooh Ullah

Science China Materials 2017 Volume 60( Issue 10) pp:985-994

Publication Date(Web):28 September 2017

DOI:10.1007/s40843-017-9106-9

In this study, a clew-like ZnO superstructure was synthesized by a copolymer-controlled self-assembly homogeneous precipitation method. Ni was impregnated to the clew-like ZnO superstructure to obtain Ni/ZnO adsorbents. The synthesized materials were characterized by scanning electron microscopy, transmission electron microscopy, N2 sorption, X-ray diffraction, Fourier transform infrared spectrometry, and H2-temperature programmed reduction techniques. The reactive adsorption desulfurization (RADS) performance of the adsorbents was evaluated in a fixed bed reactor using thiophene in n-octane as a model fuel. Sample Ni/ZnO-4h exhibits a remarkably high performance with a sulfur capacity of 189.1 mg S g–1, which is above 6 times that of the one prepared with commercial ZnO. Characterization results show that the morphology changes from micro-clews to large solid sticks with the increase of the crystallization time. The loose and open architecture of the clew-like ZnO superstructure facilitates the diffusion of reactants/products, and prevents the adsorbent particles from breakage by supplying space for the volume expansion during the RADS process. The small nanoparticles in ZnO nanostrips result in a high sulfur adsorption capacity and also favor the dispersion of Ni, leading to an excellent RADS performance.本文利用共聚物控制均匀沉淀法自组装合成了一种毛线球状ZnO超结构. 通过将Ni浸渍于该氧化锌材料上制备了一系列Ni/ZnO吸附剂. 其中, 样品Ni/ZnO-4h在反应吸附脱硫中表现出极高的硫容量(189.1 mg S g–1), 是相同条件下使用普通商业ZnO制备的Ni/ZnO-C样品的6倍. 毛线球状ZnO疏松开放的结构能够促进反应物/产物的扩散, 并抑制体积膨胀对吸附剂结构的破坏. 较小的ZnO颗粒在提供较高的硫容量的同时还能促进活性组分Ni的分散, 从而导致吸附剂具有较高的反应吸附脱硫性能.

Dispersion of nickel nanoparticles in the cages of metal-organic framework: An efficient sorbent for adsorptive removal of thiophene

Co-reporter:Sobia Aslam, Fazle Subhan, Zifeng Yan, U.J. Etim, Jingbin Zeng

Chemical Engineering Journal 2017 Volume 315(Volume 315) pp:

Publication Date(Web):1 May 2017

DOI:10.1016/j.cej.2017.01.047

•Nickel was fabricated on MIL-101 for the first time by ultrasonic assisted impregnation.•High surface area and large pore volume of MIL-101 promoted high Ni dispersion.•The present strategy save time and energy for functionalization of Ni-based MOFs.•This investigation may open an avenue of research on Ni based MOFs.Nickel NPs (<2 nm) were confined in highly porous metal organic framework (MOF; here, MIL-101(Cr)) via a facile strategy at ambient conditions. With the characterization of HRTEM, XRD, N2 physisorption, SEM, XPS, TPR, FT-IR, NH3-TPD, ICP-OES, and TG-DTG, the resulting nickel NPs up to 20 wt% first-ever were detected to be uniformly dispersed, smaller in size and easily reducible in MIL-101(Cr) cages retaining their original crystal structure. The efficiencies of the new sorbents in adsorptive removal of thiophene were investigated. Compared with pristine MIL-101, the capacity of sulfur adsorption of modified MIL-101 enhanced for thiophene, and obey the order 20Ni-MIL-101 > 10Ni-MIL-101 > 30Ni-MIL-101 > MIL-101. The improved adsorption properties were linked with surface chemistry and texture of MIL-101 support. Pseudo second-order kinetic and Langmuir models showed best fit of thiophene adsorption on MIL-101 and Ni-containing MIL-101 samples. Moreover, the rate controlling step for thiophene adsorption was intraparticle diffusion.Adsorptive desulfurization of thiophene on 20Ni-MIL-101 sorbent.Download high-res image (234KB)Download full-size image

Facile functionalization of 3-D ordered KIT-6 with cuprous oxide for deep desulfurization

Co-reporter:Fazle Subhan, Sobia Aslam, Zifeng Yan, Liu Zhen, Ayaz Ahmad, Muhammad Naeem, Jingbin Zeng, Rooh Ullah, U.J. Etim

Chemical Engineering Journal 2017 Volume 330(Volume 330) pp:

Publication Date(Web):15 December 2017

DOI:10.1016/j.cej.2017.07.151

•Ammonia assisted deposition precipitation one-step N2 reduction improves the dispersion of Cu over KIT-6.•Microenvironment of as-synthesized KIT-6 avoid aggregation of Cu NPs.•Highly dispersed Cu(NO3)2 is highly effective for Cu2O species generation.•P123 and silanols of KIT-6 improves Cu(I) production and ADS capacity.•The present strategy is time and energy saving for functionalization of Cu based mesoporous silica.Deep desulfurization by π-complexation is an efficient technique for purification of fuels. In π-complexation adsorbents, Cu(I)-based materials are effective due to low cost and high activity. However, the deep desulfurization has been proven to strongly rely on the dispersion extent of Cu species. Herein, for the first time, we report ammonia assisted deposition precipitation one-step N2 reduction strategy to fabricate Cu2O-containing KIT-6. In such strategy, Cu(NO3)2 precursor was directly introduced into the microenvironment exist between template and silica walls of template-P123-containing KIT-6 via ammonia assisted deposition precipitation. The subsequent single step N2 reduction strategy perform three functions in a single mode i.e. decomposition of Cu precursor to CuO, template removal, and conversion of CuO to Cu(I). Our strategy is convenient and efficiently promoted the dispersion of Cu species with high yield (61.84%) of Cu(I). We also demonstrated that the resultant material, as-synthesized KIT-6 supported with an optimal content 20 wt% of Cu, can capture 0.28 mmol·g−1 thiophene, which is obviously better than its counterpart CuCK-20 synthesized via calcined KIT-6. Furthermore, the thiophene adsorption activity can be recovered well without any obvious loss. Facile synthesis, high thiophene removal, and excellent regeneration ability make Cu/KIT-6 favorable for utilization in adsorptive desulfurization technology.Download high-res image (137KB)Download full-size image

Insight of synergistic effect of different active metal ions in layered double hydroxides on their electrochemical behaviors

Co-reporter:Xuejin Li, Meiyi Xin, Sheng Guo, Tonghui Cai, Dongfeng Du, Wei Xing, Lianming Zhao, Wenyue Guo, Qingzhong Xue, Zifeng Yan

Electrochimica Acta 2017 Volume 253(Volume 253) pp:

Publication Date(Web):1 November 2017

DOI:10.1016/j.electacta.2017.09.075

Recent years, there have been massive reports of layered double hydroxides (LDHs) used as electrode materials. However, the synergistic effect between different host metal ions on the electrochemical behavior of LDHs is rarely studied. We prepared a series of LDHs with different host metal combinations and investigated their physiochemical properties and redox behaviors to study the synergistic effects between different active metal ions. According to the experimental and theoretical calculation results, LDHs with dual transition metals possessed lower band-gap energies and higher conductivities than mono-transition metal-based samples. The reduced band-gap energy and enhanced conductivity should be ascribed to the hybridization between 3d-orbitals of different transition atoms. As a result, LDHs with dual transition metals exhibited lower charge transfer resistances and redox potentials as well as longer electron lifetime, implying that they could be oxidized or reduced more easily during the redox process. The lowest charge transfer resistance and longest electron lifetime of NiMn-LDHs signify that the synergistic effect between Ni and Mn is the best. From in situ X-ray photoelectron spectroscopy results, more than 50% Ni atoms in NiMn-LDHs can be oxidized under 0.45 V, which also demonstrates the excellent redox efficiency of NiMn-LDHs.Download high-res image (148KB)Download full-size image

Bifuntional petaloid nickel manganese layered double hydroxides decorated on a freestanding carbon foam for flexible asymmetric supercapacitor and oxygen evolution

Co-reporter:Xuejin Li, Jin Zhou, Xiaochen Li, Meiyi Xin, Tonghui Cai, Wei Xing, Yongming Chai, Qingzhong Xue, Zifeng Yan

Electrochimica Acta 2017 Volume 252(Volume 252) pp:

Publication Date(Web):20 October 2017

DOI:10.1016/j.electacta.2017.08.028

In this work, we develop a bifunctional composite comprised of hierarchical flower-like NiMn-layered double hydroxides (LDH) nanoarrays grown on melamine sponge-derived carbon (SC). This composite material is used as a flexible asymmetric supercapacitor positive electrode and oxygen evaluation reaction (OER) electrocatalyst. Integrated carbon foams with controllable three-dimensional pores are easily obtained and served as conductive backbones for the growth of the flower-like NiMn-LDH nanoarrays. The as-prepared flexible electrode, combining a highly open scaffold-like structure with well-designed electron transfer channels, shows significantly enhanced cyclic stability (99.6% of the initial activity maintained after 5000 cycles) and high energy density (41.0 Wh·Kg−1) in aqueous electrolyte. The as-prepared SC@NiMn-LDH@G//NPC asymmetric supercapacitor can lighten a LED indicator for more than 10 minutes. Additionally, this composite presents extremely low overpotentials (220 mV at 10 mA·cm−2) and low Tafel slopes (30 mV·dec−1) in alkaline medium. This OER performance is one of the best reported so far among the state of art electrocatalysts.

Remarkable supercapacitor performance of petal-like LDHs vertically grown on graphene/polypyrrole nanoflakes

Co-reporter:Dongfeng Du;Xiaozhong Wu;Shuo Li;Yu Zhang;Wei Xing;Li Li;Qingzhong Xue;Peng Bai;Zifeng Yan

Journal of Materials Chemistry A 2017 vol. 5(Issue 19) pp:8964-8971

Publication Date(Web):2017/05/16

DOI:10.1039/C7TA00624A

A 3D hybrid nanostructure, in which petal-like ultrathin nickel–aluminum layered double hydroxides (LDHs) were vertically grown on a conductive graphene/polypyrrole (GP) substrate, was designed and fabricated by a facile hydrothermal method. SEM and TEM observations confirmed the successful synthesis of this specially designed nanostructure, in which the conductive substrate ensures very fast electron transfer during the charge–discharge process, whereas the 3D hierarchical structure facilitates rapid ion transfer. The ultrathin LDH nanoflakes (3–5 nm) expose their abundant active sites to the electrolyte, thus generating huge pseudocapacitance. Combining the abovementioned features, this specially designed 3D nanostructured hybrid possesses an exceptional specific capacitance (2395 F g−1 at 1 A g−1), excellent rate performance (retaining 71.8% of capacitance at the current density of 20 A g−1), and remarkable cycling stability (99.6% retention after 10 000 cycles). Moreover, the assembled asymmetric supercapacitor obtained using GP@LDH as a positive electrode and GP-derived carbon as a negative electrode exhibits an ultrahigh energy density of 94.4 W h kg−1 at the power density of 463.1 W kg−1, making GP@LDH very attractive as an electrode material for high performance and low-cost supercapacitors.

Sandwich-like nitrogen-doped porous carbon/graphene nanoflakes with high-rate capacitive performance

Co-reporter:Yu Zhang, Binglin Tao, Wei Xing, Lei Zhang, Qingzhong Xue and Zifeng Yan

Nanoscale 2016 vol. 8(Issue 15) pp:7889-7898

Publication Date(Web):30 Nov 2015

DOI:10.1039/C5NR05151G

Sandwich-like nitrogen-doped porous carbon/graphene nanoflakes (NPCFs) are prepared via a two-step approach, firstly by using in situ polymerization of pyrrole (Py) on the surface of graphene oxide (GO) and then by KOH activation under an Ar atmosphere. As the shape-directing agent and conductive matrix, graphene sheets play an important role in enhancing NPCFs’ electrochemical performance. The NPCFs exhibit high specific surface area (2502 m2 g−1), short ion diffusion path (ca. 30 nm), high conductivity (72 S m−1) and a considerable nitrogen level (6.3 wt%). These intriguing features render NPCFs a promising electrode material for electrochemical supercapacitors, which displays high specific capacitance (341 F g−1), excellent rate capability (over 71% retention ratio at 50 A g−1) and outstanding cycling stability (almost no capacitance loss after 2000 cycles) in a 30 wt% KOH aqueous electrolyte. Besides, the assembled symmetrical supercapacitor delivers a high gravimetric energy density of 11.3 Wh kg−1 in an aqueous electrolyte and 66.4 Wh kg−1 in an organic electrolyte.

Comment on “Ultrahigh Performance Supercapacitor from Lacey Reduced Graphene Oxide Nanoribbons”

Co-reporter:Xiaozhong Wu, Wei Xing, and Zifeng Yan

ACS Applied Materials & Interfaces 2016 Volume 8(Issue 40) pp:26427

Publication Date(Web):September 28, 2016

DOI:10.1021/acsami.6b02157

Relationship between Surface Chemistry and Catalytic Performance of Mesoporous γ-Al2O3 Supported VOX Catalyst in Catalytic Dehydrogenation of Propane

Co-reporter:Peng Bai, Zhipeng Ma, Tingting Li, Yupeng Tian, Zhanquan Zhang, Ziyi Zhong, Wei Xing, Pingping Wu, Xinmei Liu, and Zifeng Yan

ACS Applied Materials & Interfaces 2016 Volume 8(Issue 39) pp:25979

Publication Date(Web):September 16, 2016

DOI:10.1021/acsami.6b07779

Mesoporous γ-Al2O3 was synthesized via a cation–anion double hydrolysis approach (CADH). The synthesized mesoporous alumina displayed a relatively high surface area, a large pore volume and a narrow pore size distribution. By applying the mesoporous alumina as a support, supported vanadium catalysts were prepared and evaluated in the dehydrogenation of propane, exhibiting a superior catalytic performance over that supported on a commercial alumina. Materials were characterized with a variety of techniques such as X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet–visible spectroscopy, 51V magnetic angle spinning nuclear magnetic resonance, Raman spectroscopy, Fourier transformed infrared spectroscopy of pyridine adsorption and thermogravimetric-differential thermal analysis. The correlated structure–performance relationship of catalysts reveals that a higher crystallization temperature endows mesoporous alumina materials with more surface acid sites, favoring the formation of polymerized VOX species, which are more active than isolated ones in the propane dehydrogenation, resulting in a better catalytic performance. The established relationship between surface chemistry and catalytic performance of supported VOX catalysts suggests that a superior vanadium catalyst for propane dehydrogenation could be achieved by rationally enriching the concentration of polymeric VOX species on the catalyst, which can be realized by tuning the surface acidity of alumina support.Keywords: mesoporous γ-Al2O3; polymerized VOX species; propane dehydrogenation; surface acidity; vanadium-based catalyst

Effect of vanadium contamination on the framework and micropore structure of ultra stable Y-zeolite

Co-reporter:U.J. Etim, B. Xu, Rooh Ullah, Z. Yan

Journal of Colloid and Interface Science 2016 Volume 463() pp:188-198

Publication Date(Web):1 February 2016

DOI:10.1016/j.jcis.2015.10.049

Y-zeolites are the main component of fluid catalytic cracking (FCC) catalyst for conversion of crude petroleum to products of high demand including transportation fuel. We investigated effects of vanadium which is present as one of the impurities in FCC feedstock on the framework and micropore structure of ultra-stable (US) Y-zeolite. The zeolite samples were prepared and characterized using standard techniques including: (1) X-ray diffraction, (2) N2 adsorption employing non local density functional theory method, NLDFT, (3) Transmittance and Pyridine FTIR, (4) Transmittance electron microscopy (TEM), and (5) 27Al and 29Si MAS-NMR. Results revealed that in the presence of steam, vanadium caused excessive evolution of non inter-crystalline mesopores and structural damage. The evolved mesopore size averaged about 25.0 nm at 0.5 wt.% vanadium loading, far larger than mesopore size in zeolitic materials with improved hydrothermal stability and performance for FCC catalyst. A mechanism of mesopore formation based on accelerated dealumination has been proposed and discussed. Vanadium immobilization experiments conducted to mitigate vanadium migration into the framework clearly showed vanadium is mobile at reaction conditions. From the results, interaction of vanadium with the passivator limits and decreases mobility and activity of vanadium into inner cavities of the zeolite capable of causing huge structure breakdown and acid sites destruction. This study therefore deepens insight into the causes of alteration in activity and selectivity of vanadium contaminated catalyst and hints on a possible mechanism of passivation in vanadium passivated FCC catalyst.

Effects of synthetic conditions on the textural structure of pseudo-boehmite

Co-reporter:Yang Yang, Yanyan Xu, Baozhai Han, Benjing Xu, Xinmei Liu, Zifeng Yan

Journal of Colloid and Interface Science 2016 Volume 469() pp:1-7

Publication Date(Web):1 May 2016

DOI:10.1016/j.jcis.2016.01.053

Mesoporous alumina with pseudo-boehmite phase was prepared by using the cation–anion double hydrolysis method from mixed aqueous solution of aluminum sulfate and sodium aluminate. The effect of synthetic conditions on the crystal structure and textual properties of pseudo-boehmite was investigated, such as synthetic temperature, pH value and the addition of sodium silicate. With the assistance of characterization techniques, such as X-ray diffraction (XRD), N2 adsorption–desorption isotherms (BET) and 27Al magic-angle spinning nuclear magnetic resonance (MAS NMR), the relationship between textural properties of the mesoporous alumina samples and their synthetic conditions was discussed. The results displayed that an increase in synthesis temperature promoted the formation of higher crystalline pseudo-boehmite with the increase of its surface area and pore volume. Pure pseudo-boehmite phase could be obtained in the pH value range from 6.0 to 9.0, while bayerite phase occurred when the pH value was over 10.0. The introduction of sodium silicate could greatly improve the pore volume (1.20 cm3/g) and surface area (480.2 m2/g) of pseudo-boehmite. Interestingly, pure pseudo-boehmite phase was obtained at very high pH value without formation of bayerite phase when sodium silicate was initially added into the aluminum hydroxide colloid.

One-Pot Cation–Anion Double Hydrolysis Derived Ni/ZnO–Al2O3 Absorbent for Reactive Adsorption Desulfurization

Co-reporter:Rooh Ullah, Zhanquan Zhang, Peng Bai, Pingping Wu, Dezhi Han, U. J. Etim, and Zifeng Yan

Industrial & Engineering Chemistry Research 2016 Volume 55(Issue 13) pp:3751

Publication Date(Web):March 17, 2016

DOI:10.1021/acs.iecr.5b04421

In this study, a series of Ni/ZnO–Al2O3 adsorbents were synthesized by a one-pot cation–anion double hydrolysis (CADH) method. The materials were characterized by N2 sorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet–visible diffuse reflectance spectroscopy (UV–vis), Raman spectroscopy, and H2 temperature-programmed reduction (H2-TPR). The reactive adsorption desulfurization (RADS) performance of the adsorbents was evaluated in a fixed bed reactor using thiophene in n-octane as a model fuel. Results showed that the adsorbents exhibited better RADS performance than those prepared using the conventional kneading method. The thiophene conversion and sulfur capacity of adsorbents decreased with increasing the crystallization temperature. Among all tested adsorbents, the Ni/ZnO–Al2O3 sample prepared at 28 °C presented the largest adsorption capacity and highest RADS reactivity. Textual characterization results indicated that the sample Ni/ZnO–Al2O3(28 °C) possessed relatively bigger pore size and larger pore volume than other samples, which may alleviate the pore shrinkage/blockage during the RADS process. A combination of XRD, UV–vis, and H2-TPR characterization results demonstrate that a high crystallization temperature favors the growth of inactive ZnAl2O4 crystals and induce the formation of more less-reducible Ni2+ ion, causing the loss of active ZnO phase and Ni0 atoms, which may be the reason for the lower RADS activity of the adsorbent synthesized at higher crystallization temperatures.

Comparison of the Reactive Adsorption Desulfurization Performance of Ni/ZnO–Al2O3 Adsorbents Prepared by Different Methods

Co-reporter:Rooh Ullah, Peng Bai, Pingping Wu, Zhanquan Zhang, Ziyi Zhong, U. J. Etim, Fazle Subhan, and Zifeng Yan

Energy & Fuels 2016 Volume 30(Issue 4) pp:2874-2881

Publication Date(Web):March 22, 2016

DOI:10.1021/acs.energyfuels.6b00232

In this study, a series of Ni/ZnO–Al2O3 mixed oxide (MO) adsorbents were prepared by the one-step homogeneous precipitation method and the cation–anion double hydrolysis (CADH) method for reactive adsorption desulfurization (RADS) using thiophene as a model fuel in a fixed bed reactor. The synthesized adsorbents were characterized by N2 sorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), H2 temperature-programmed reduction (H2-TPR), ultraviolet–visible (UV–vis) diffuse reflectance spectroscopy (DRS), and Raman spectroscopy. Results show that both Ni loading and the preparation method have a significant effect on the RADS activities of the adsorbent. Among the studied adsorbents, 10% Ni/ZnO–Al2O3 prepared by the one-step urea precipitation method showed the best RADS performance, with a thiophene conversion up to 96% and a sulfur adsorption capacity of 86 mg of S/g, which is 34% larger than that of CADH adsorbents. In addition, upon five RADS–regeneration cycles, sample 10% Ni/ZnO–Al2O3 exhibited a drop of only 3% in thiophene conversion, indicating the high stability of the Ni/ZnO–Al2O3 adsorbent prepared by homogeneous precipitation. Characterization results show that the one-step homogeneous precipitation method could facilitate the formation of small ZnO particles while suppressing the formation of inactive ZnAl2O4. On the other hand, by decreasing the formation of NiAl2O4, the homogeneous precipitation method could also generate high concentration of Ni0 sites, which are the active centers for the hydrogenolysis of C–S bonds. These findings indicate that a high-performance adsorbent for RADS can be obtained by employing a proper preparation method with good control on the adsorbent structure.

In-Depth Insight into the Chemical Composition of Bio-oil from Hydroliquefaction of Lignocellulosic Biomass in Supercritical Ethanol with a Dispersed Ni-Based Catalyst

Co-reporter:Qingyin Li, Dong Liu, Pingping Wu, Linhua Song, Chongchong Wu, Jing Liu, Xiaomin Shang, Zifeng Yan, and Fazle Subhan

Energy & Fuels 2016 Volume 30(Issue 7) pp:5269

Publication Date(Web):May 9, 2016

DOI:10.1021/acs.energyfuels.6b00201

A comprehensive compositional analysis was conducted on biofuel obtained from woody biomass hydroliquefaction in supercritical ethanol with a dispersed Ni-based catalyst. Gas chromatography–mass spectrometry (GC–MS) and 1H nuclear magnetic resonance (NMR) were used to analyze the bio-oil compositions, and the results indicated the presence of carboxylic acid, ethyl ester, aldehyde, ketone, phenol, and its derivatives. As a result of the inherent limitations of these techniques, an intensive compositional characterization of bio-oil was accomplished through Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The results revealed that the dominant oxygen-containing compounds were O2–O13 with double bond equivalent (DBE) values of 1–20 and carbon numbers of 10–25. The minor N1Ox class species with 4–15 carbon numbers and 10–35 DBE were also detected. The use of FT-ICR MS provided an in-depth compositional analysis of liquefaction-derived oil and would improve the understanding of biocrude for further process upgrading.

Improved catalytic cracking performance of USY in the presence of metal contaminants by post-synthesis modification

Co-reporter:U.J. Etim, Benjing Xu, Zhen Zhang, Ziyi Zhong, Peng Bai, Ke Qiao, Zifeng Yan

Fuel 2016 Volume 178() pp:243-252

Publication Date(Web):15 August 2016

DOI:10.1016/j.fuel.2016.03.060

•Zeolite Y with interconnected mesoporous was prepared by post synthesis modification.•Modified catalysts showed improved catalytic behavior in the presence of contaminant metals.•The introduction of mesopores increased yields of light oil product with lower coke and gas yields.•Improved structural properties caused superior performance.It is well known that pores in catalysts larger than reactant molecules in dimension can ease flow resistance and enhance desorption of the molecules. In this work, mesoporosity was introduced into ultra-stable Y zeolite (USY) via a soft-templating method and the resulting zeolite was applied for preparation of fluid catalytic cracking (FCC) catalysts. The zeolite was extensively characterized by methods including N2 sorption, X-ray Diffraction (XRD), magic angle spinning nuclear magnetic resonance (MAS NMR), Fourier transformed infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. Results show that the resulting zeolite pores were highly interconnected. Aluminum atoms were re-distributed within the framework while the crystallites were maintained. The effect of contaminant metals (vanadium and nickel) on the activity and product distribution of the prepared catalysts containing modified zeolite was investigated using the micro activity test (MAT). Compared with the parent USY, the modified USY exhibited higher yields of light oil products, much lower coke formation, and lower dry gas yield. Furthermore, the catalysts containing modified USY-10 possessed a higher stability toward metal deactivation than the parent USY. This improved catalytic behavior could be attributed not only to the enhanced diffusion and faster desorption of the adsorbed oil molecules within the pores, but also to the increased accessibility to the acidic sites due to well interconnected pore structures and the large mesopore size.Modification of a commercial USY introduces interconnected mesopores with bimodal pore size distribution. This developed features cause improvement in the fluid catalytic cracking performance of the zeolite catalyst. Generally, light oil yields increased, while coke and gas yields decreased.

Investigation of solvent effect on the hydro-liquefaction of sawdust: An innovative reference approach using tetralin as chemical probe

Co-reporter:Qingyin Li, Dong Liu, Linhua Song, Pingping Wu, Zifeng Yan, Min Li

Fuel 2016 Volume 164() pp:94-98

Publication Date(Web):15 January 2016

DOI:10.1016/j.fuel.2015.09.076

•Tetralin is firstly utilized as chemical probe to investigate the solvent effects on the sawdust liquefaction.•The higher solvent impact index is consistent with higher sawdust conversion and bio-oil yield.•The temperature and solvent type have an influence on the solvent effect in the liquefaction process.•The analysis results showed that product compositions highly depend on the employed solvents.An innovative reference approach was developed to investigate the solvent effects on the liquefaction of sawdust by using tetralin as a chemical probe, and the corresponding solvent impact index was defined in this study. The influence of reaction conditions including reaction temperature and solvent types on solvent impact index were discussed. It was found that larger solvent impact index corresponds to improved sawdust conversion and higher bio-oil yield. The liquid and gaseous products obtained were characterized by 1H nuclear magnetic resonance (1H NMR), gas chromatography (GC), and elemental analysis (EA). The component of products highly depended on the employed solvents.

Monte Carlo simulation study of the halogenated MIL-47(V) frameworks: influence of functionalization on H2S adsorption and separation properties

Co-reporter:Jing Xu;Wei Xing;Haifeng Wang;Wenbin Xu;Qiuyue Ding

Journal of Materials Science 2016 Volume 51( Issue 5) pp:2307-2319

Publication Date(Web):2016 March

DOI:10.1007/s10853-015-9539-2

Monte Carlo simulation calculations were performed to explore the H2S adsorption and separation in the initial MIL-47(V) and the monohalogenated MIL-47(V)-X (X = F, Cl, Br). Both initial and halogenated MIL-47(V) metal–organic framework materials (MOFs) exhibit an ultra-high H2S adsorption ability, which is much higher than that of CH4 and N2. Halogen functionalization could enhance the H2S uptake in unit volume of MOFs especially in low-pressure range, with the sequence: MIL-47(V) < MIL-47(V)-F < MIL-47(V)-Cl < MIL-47(V)-Br, according with the increasing polarizability of the linkers, whereas the H2S mass fraction follows an inverse order MIL-47(V) > MIL-47(V)-F > MIL-47(V)-Cl > MIL-47(V)-Br, because of the increasing mass density of MOFs after halogenation. The adsorption behavior of four MOFs for the H2S/CH4 and H2S/N2 mixtures are explored as a function of both pressure and H2S mole fraction, and all of four MOFs show the ultraselectivity toward H2S molecule. Compared to the initial MIL-47(V), the halogenated MOFs exhibit the preferable H2S/CH4 and H2S/N2 selectivity under the conditions of low temperature, high pressure, and high H2S mole fraction.

Modification of USY zeolites with malic–nitric acid for hydrocracking

Co-reporter:Ke Qiao;Xuejin Li;Yang Yang;Fazle Subhan;Xinmei Liu

Applied Petrochemical Research 2016 Volume 6( Issue 4) pp:353-359

Publication Date(Web):2016 December

DOI:10.1007/s13203-015-0145-7

The modification of commercial ultra-stable Y zeolite using malic acid (MA) and nitric acid (NA) was investigated. A series of factors including the amount of MA and NA solutions, the pH of the solutions, the treatment time, and the reaction temperature were investigated and optimized. The pore structure, acid properties, and crystal structure of modified USY zeolite were characterized by N2-adsorption, temperature-programmed desorption of ammonia (NH3-TPD), pyridine adsorbed Fourier transform infrared spectroscopy, and X-ray diffraction techniques. The as-obtained sample under the optimum conditions presents an increased secondary pore volume up to 0.202 cm3 g−1, which accounts for 45.3 % of the total pore volume, and appropriate acid properties as well as good crystallinity. Furthermore, the USY zeolite modified with different methods was also investigated, indicating that malic–nitric combined acid is an effective modifier for USY zeolite. The modified USY zeolite was used as support to prepare hydrocracking catalysts. The 140–370 °C middle distillate yield of the catalyst is 68.59 %, and middle distillate selectivity can reach up to 81.52 %. Compared with commercial catalyst, the yield and selectivity increased by 8.17 and 5.14 %, respectively.

Hyper-Branched Cu@Cu2O Coaxial Nanowires Mesh Electrode for Ultra-Sensitive Glucose Detection.

Co-reporter:Yuxin Zhao, LiLi Fan, Ying Zhang, Hu Zhao, Xuejin Li, Yanpeng Li, Ling Wen, Zifeng Yan, and Ziyang Huo

ACS Applied Materials & Interfaces 2015 Volume 7(Issue 30) pp:16802

Publication Date(Web):July 17, 2015

DOI:10.1021/acsami.5b04614

Electrode design in nanoscale is expected to contribute significantly in constructing an enhanced electrochemical platform for a superb sensor. In this work, we present a facile synthesis of new fashioned heteronanostructure that is composed of one-dimensional Cu nanowires (NWs) and epitaxially grown two-dimensional Cu2O nanosheets (NSs). This hierarchical architecture is quite attractive in molecules detection for three unique characteristics: (1) the three-dimensional hierarchical architecture provides large specific surface areas for more active catalytic sites and easy accessibility for the target molecules; (2) the high-quality heterojunction with minimal lattice mismatch between the built-in current collector (Cu core) and active medium (Cu2O shell) considerably promotes the electron transport; (3) the adequate free space between branches and anisotropic NWs can accommodate a large volume change to avoid collapse or distortion during the reduplicative operation processes under applied potentials. The above three proposed advantages have been addressed in the fabricated Cu@Cu2O NS-NW-based superb glucose sensors, where a successful integration of ultrahigh sensitivity (1420 μA mM–1 cm–2), low limit of detection (40 nM), and fast response (within 0.1 s) has been realized. Furthermore, the durability and reproducibility of such devices made by branched core–shell nanowires were investigated to prove viability of the proposed structures. This achievement in current work demonstrates an innovative strategy for nanoscale electrode design and application in molecular detection.Keywords: core−shell; epitaxial growth; glucose sensor; hierarchical structures; nanowires

Insight into high areal capacitances of low apparent surface area carbons derived from nitrogen-rich polymers

Co-reporter:Xiaozhong Wu, Jin Zhou, Wei Xing, Yu Zhang, Peng Bai, Benjing Xu, Shuping Zhuo, Qingzhong Xue, Zifeng Yan

Carbon 2015 Volume 94() pp:560-567

Publication Date(Web):November 2015

DOI:10.1016/j.carbon.2015.07.038

The energy storage mechanism of N-doped carbons with low apparent specific surface areas (Brunauer–Emmett–Teller specific surface area determined by N2 adsorption) has puzzled the researchers in the supercapacitor field in recent years. In order to explore this scientific problem, such carbon materials were prepared through pyrolysis of N-rich polymers such as melamine formaldehyde resin and polyaniline. Although these carbons possess low apparent specific surface areas of no more than 60 m2 g−1, their areal capacitance could reach up to an abnormally high value of 252 μF cm−2. The results of systematical materials characterizations and electrochemical measurements show that these carbons contain numerous ultramicropores which could not be detected by the adsorbate of N2 but are accessible to CO2 and electrolyte ions. These ultramicropores play dominant roles in the charge storage process for these low apparent surface area carbons, leading to an energy storage mechanism of electric double layer capacitance. The contribution of pseudocapacitance to the total capacitance is calculated to be less than 15%. This finding challenges the widely accepted viewpoint that the high capacitance of N-doped carbon is mainly attributed to the pseudocapacitance generated from the faradic reactions between nitrogen functionalities and electrolyte.

Superhigh-rate capacitive performance of heteroatoms-doped double shell hollow carbon spheres

Co-reporter:Tonghui Cai, Wei Xing, Zhen Liu, Jingbin Zeng, Qingzhong Xue, Shizhang Qiao, Zifeng Yan

Carbon 2015 Volume 86() pp:235-244

Publication Date(Web):May 2015

DOI:10.1016/j.carbon.2015.01.032

The salient practical application feature of an ideal supercapacitor is its ability to deliver high energy density stably even at ultrahigh power density. Therefore, a rational design of electrode materials is essentially required for achieving high current, energy and power densities. In this work, a special “in situ replicating” strategy is employed to fabricate double shell hollow carbon spheres with homogeneously doped heteroatoms. The KOH activation introduces micropores to the thin shells of the hollow carbon spheres. Materials characterizations show that these carbon spheres have such merits as large surface area, easy-accessible micropore surface with faradaic reaction sites, and high conductivity. All these result in ultrafast ion transport from electrolyte to the micropores in the carbon spheres and endow the carbon with outstanding capacitive performance, e.g., an unprecedentedly high specific capacitance of 270 F g−1 at a very high current density of 90 A g−1. Moreover, a high energy density of 11.9 Wh kg−1 at a respectable power density of 30,000 W kg−1 is achieved in 6 M KOH electrolyte.

A colorimetric assay for measuring iodide using Au@Ag core–shell nanoparticles coupled with Cu2+

Co-reporter:Jingbin Zeng, Yingying Cao, Chun-Hua Lu, Xu-dong Wang, Qianru Wang, Cong-ying Wen, Jian-Bo Qu, Cunguang Yuan, Zi-feng Yan, Xi Chen

Analytica Chimica Acta 2015 Volume 891() pp:269-276

Publication Date(Web):3 September 2015

DOI:10.1016/j.aca.2015.06.043

•Au@Ag core–shell NPs were synthesized and coupled with Cu2+ for the colorimetric I− sensing.•This assay is simple, rapid and selective.•Au@Ag core–shell NPs-Cu2+ were embedded into agarose gels as test strips.Au@Ag core–shell nanoparticles (NPs) were synthesized and coupled with copper ion (Cu2+) for the colorimetric sensing of iodide ion (I−). This assay relies on the fact that the absorption spectra and the color of metallic core–shell NPs are sensitive to their chemical ingredient and dimensional core-to-shell ratio. When I− was added to the Au@Ag core–shell NPs-Cu2+ system/solution, Cu2+ can oxidize I− into iodine (I2), which can further oxidize silver shells to form silver iodide (AgI). The generated Au@AgI core–shell NPs led to color changes from yellow to purple, which was utilized for the colorimetric sensing of I−. The assay only took 10 min with a lowest detectable concentration of 0.5 μM, and it exhibited excellent selectivity for I− over other common anions tested. Furthermore, Au@Ag core–shell NPs-Cu2+ was embedded into agarose gels as inexpensive and portable “test strips”, which were successfully used for the semi-quantitation of I− in dried kelps.

Effects of dissolution alkalinity and self-assembly on ZSM-5-based micro-/mesoporous composites: a study of the relationship between porosity, acidity, and catalytic performance

Co-reporter:Peng Peng, Youhe Wang, Mark J. Rood, Zhanquan Zhang, Fazle Subhan, Zifeng Yan, Lihong Qin, Zhihua Zhang, Zhongdong Zhang and Xionghou Gao

CrystEngComm 2015 vol. 17(Issue 20) pp:3820-3828

Publication Date(Web):15 Apr 2015

DOI:10.1039/C5CE00384A

ZSM-5-based micro-/mesoporous composites have attracted extensive attention as a promising material that could be industrialized in the near future. The hierarchical structure and catalytic performance of the ZSM-5-based hierarchical composite are highly dependent on its treatment conditions. Of these synthesis parameters, dissolution alkalinity is the most important one. However, systematic studies on the effects of dissolution alkalinity, specifically those that discuss the relationship between porosity, acidity, and catalytic performance in ZSM-5-based hierarchical composites by the combined dissolution and self-assembly method, have not yet been reported. In this article, the porosity and acidity of ZSM-5-based micro-/mesoporous composite samples made by select dissolution alkalinities are systematically investigated. Various characterization techniques illustrate that three different groups of ZSM-5-based micro-/mesoporous composites are classified based on their distinctive indexed hierarchical factor values, I through III. Group I, treated with 0 to 0.5 mol L−1 NaOH, is mesoporous ZSM-5 attached by Al-MCM-41-like ordered mesostructures and has a high yield for liquid petroleum gas. Group II, treated with 0.5 mol L−1 to 1.0 mol L−1 NaOH, is a mixture of ZSM-5 zeolite phase and Al-MCM-41-like ordered mesostructure phase and has a high yield of light oil. Group III, treated with 1.0 mol L−1 NaOH, is formed by complete collapse of ZSM-5 crystals and formation of Al-MCM-41-like ordered mesostructures and exhibits a high yield of total liquid oil. Due to increasingly enhanced accessibility of acid sites (indexed as accessibility index), all three groups of ZSM-5-based micro-/mesoporous composites show comparable conversion for vacuum gas oil cracking compared with their parent counterpart. These results are of vital importance during the selection of the synthesis conditions and scale-up tests of ZSM-5-based micro-/mesoporous composites to selectively produce liquid petroleum gas, light oil, and total liquid oil.

Rapid functionalization of as-synthesized KIT-6 with nickel species occluded with template for adsorptive desulfurization

Co-reporter:Sobia Aslam, Fazle Subhan, Zifeng Yan, Wei Xing, Jingbin Zeng, Yuxiang Liu, Muhammad Ikram, Sadia Rehman, Rooh Ullah

Microporous and Mesoporous Materials 2015 Volume 214() pp:54-63

Publication Date(Web):15 September 2015

DOI:10.1016/j.micromeso.2015.04.032

•Nickel based as-synthesized KIT-6 (Ni-KIT-6) was synthesized by solid-state grinding.•Silanols and micro environment promoted high dispersion of nickel species.•Ni-KIT-6 showed high desulfurization activity for desulfurization of fuels.•Desulfurization capacity depended on the dispersion degree of nickel species.•100% of adsorptive desulfurization capacity of the spent Ni-KIT-6 can be recovered.Nickel-containing mesoporous silica, Ni-KIT-6, was prepared by directly grinding nickel nitrate into the as-synthesized KIT-6 occluded with template for adsorptive desulfurization of fuels. The obtained materials were well-characterized by N2 adsorption, XRD, HRTEM, H2-TPR, FT-IR, XPS and TG/DTG. The results reveal that the abundant silanols, as well as the confined space between silica walls and template in as-synthesized KIT-6 are highly efficient in dispersing large amount of nickel oxide in the channels of mesoporous silica. Compared with the material synthesized using calcined KIT-6, Ni-KIT-6 demonstrates extremely smaller Ni particles on the support, stronger interaction of Ni with silica matrix and higher content of active Ni0 in the KIT-6. As a result, the adsorptive desulfurization performance of Ni-KIT-6, both in commercial and model fuels was enhanced. The present strategy not only saves time and energy, but also allows template removal and precursor conversion in one step instead of repeated calcinations in conventional methods. After regeneration of spent sorbent, approximately 100% of adsorption capacity was recovered.

Surface chemistry and catalytic performance of chromia/alumina catalysts derived from different potassium impregnation sequences

Co-reporter:Daolan Liu, Peng Bai, Pingping Wu, Dezhi Han, Yongming Chai, Zifeng Yan

Applied Surface Science 2015 Volume 351() pp:250-259

Publication Date(Web):1 October 2015

DOI:10.1016/j.apsusc.2015.05.128

Highlights

•: Impregnation sequence influenced the surface acidity and Cr species distribution.
•: Cr/K/Al₂O₃ with K doped prior to Cr exhibited better catalytic performance.
•: Catalyst Cr/K/Al₂O₃ possesses mainly polymeric chromium species.
•: Catalyst K/Cr/Al₂O₃ possesses mainly oligomeric and isolated chromium species.
•: Oligomeric and isolated chromium species were more inclined to form coke deposits.

Study on the Desulfurization of High-Sulfur Crude Oil by the Electrochemical Method

Co-reporter:Dong Liu, Ming Li, Raja L. Al-Otaibi, Linhua Song, Wen Li, Qingyin Li, Hamid O. Almigrin, and Zifeng Yan

Energy & Fuels 2015 Volume 29(Issue 11) pp:6928-6934

Publication Date(Web):September 27, 2015

DOI:10.1021/acs.energyfuels.5b01242

The SnSb intermetallic compound was synthesized by chemical precipitation with NaBH4 as a reducer, and then it was applied in the electrodesulfurization of Saudi crude oil as functional desulfurization material. The prepared SnSb intermetallic compound was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectrometry (EDS). Additionally, the raw material and treated oil were analyzed through gas chromatography–pulsed flame photometric detector (GC–PFPD) and gas chromatography–mass spectrometry (GC–MS). The results showed that the SnSb intermetallic compound was restored with NaBH4 with a larger particle size, lower surface area, lower crystallinity, and “brick-shaped” structure. The desulfurization efficiency for sulfocompounds with a small molecular weight is higher. It should be especially noted that benzonaphthothiophene was hardly removed by traditional hydrogenation desulfurization, whereas it could be subtracted partly via electrochemical adsorption desulfurization. The proposed desulfurization mechanism would be attributed to the adsorption reactions on the surface of the SnSb intermetallic compound.

Hierarchical SAPO-11 preparation in the presence of glucose

Co-reporter:Zhen Liu, Lingjing Liu, Hao Song, Chuangye Wang, Wei Xing, Sridhar Komarneni, Zifeng Yan

Materials Letters 2015 Volume 154() pp:116-119

Publication Date(Web):1 September 2015

DOI:10.1016/j.matlet.2015.04.067

•Hierarchical SAPO-11 molecular sieves are prepared in the presence of glucose.•Intercrystaline meso-structures are confirmed by SEM and TEM.•Carbon nanoshell and nanoparticles are responsible for the mesopores formation.Glucose was used as a mesoporous structure directing agent to synthesize hierarchical porous silicoaluminophosphate molecular sieves with AEL topology (SAPO-11). Nanosized SAPO-11 with numerous mesopores were confirmed by X-ray diffraction (XRD) and N2 adsorption–desorption analysis. Scanning electron microscopy (SEM) and transimission electron microscopy (TEM) are employed to reveal that inter-crystallinic meso-structures were formed from the aggregation of nanosized crystallites. A proposed mesopore construction mechanism by the addition of glucose is presented based on Energy Dispersive X-ray Spectroscopy (EDS) and CHNS analysis.

Hydro-liquefaction of woody biomass for bio-oil in supercritical solvent with [BMIM]Cl/NiCl2 catalyst

Co-reporter:Qingyin Li;Peng peng;Dong Liu;Min Li;Linhua Song

Applied Petrochemical Research 2015 Volume 5( Issue 4) pp:363-369