Co-reporter:Aiping Chen, Huijun Guo, Yumeng Song, Ping Chen, Hui Lou
International Journal of Hydrogen Energy 2017 Volume 42, Issue 15(Volume 42, Issue 15) pp:
Publication Date(Web):13 April 2017
DOI:10.1016/j.ijhydene.2017.03.092
•CeO2–ZrO2 and CeO2–TiO2 mixed oxides exhibited excellent hydrothermal stability.•Pt/C1Z1 and Pt/C1T1 showed superior catalytic activity and H2 selectivity.•Pt/C1Z1 and Pt/C1T1 exhibited excellent recyclability.•Pt/C1Z1 and Pt/C1T1 can be used to substitute hydrothermal unstable Pt/Al2O3.In this study, a series of CeO2–ZrO2 and CeO2–TiO2 materials with different composition were prepared, characterized by BET and XRD analysis, and their hydrothermal stability was studied by subjecting the samples to acetic acid solutions at 533 K. All of the materials, especially C1Z1 (50 mol% CeO2 with 50 mol% ZrO2) and C1T1 (50 mol% CeO2 with 50 mol% TiO2), exhibited excellent stability with no phase transformation and minimal decrease in their specific surface area (SSA) was observed even after 16 h. After being loaded by Pt, these catalysts were used for the aqueous phase reforming (APR) of the low-boiling fraction of bio-oil (LBF) to investigate their catalytic performance. Among these catalysts Pt/C1Z1 and Pt/C1T1 showed superior catalytic activity, probably due to their lowest reduction temperature and the largest amount of O vacancies generated by the reduction of the surface oxygen of well-dispersed CeO2. Thus, Pt/C1Z1 and Pt/C1T1 were chosen to investigate their recyclability. The catalytic activity and H2 selectivity of Pt/C1Z1 and Pt/C1T1 can be almost recovered after being calcined in air at 773 K for regeneration. After three cycles, the particle size of Pt/C1Z1 and Pt/C1T1 only experienced a slight increase, while for Pt/Al2O3 it increased from 2.9 nm to 7.8 nm. So, compared with Pt/Al2O3, the Pt/C1Z1 and Pt/C1T1 catalysts were identified as effective and recyclable candidates for the production of H2 rich fuel gas from APR of LBF.
Co-reporter:Gang Feng, Ping Chen and Hui Lou
Catalysis Science & Technology 2015 vol. 5(Issue 4) pp:2300-2304
Publication Date(Web):26 Jan 2015
DOI:10.1039/C4CY01647E
Phenol is an important component of pyrolysis bio-oil, especially from lignin, and the conversion of phenol is crucial for the production of biofuel. A cost-effective and efficient catalyst is worth developing in the hydrogenation of phenol. Herein we report that supported palladium nanoparticles on carbon–nitrogen composites with high surface area are highly active for aqueous-phase hydrogenation of phenol. The conversion of phenol was 91.7% within 1 h at 80 °C. Higher activity was achieved at higher temperature. The synergy between palladium nanoparticles and the carbon–nitrogen composite support accelerated the hydrogenation of phenol, which clarified the crucial role played by the support. The hydrogenation of phenol highlights the potential of these catalysts for upgrading bio-oil.
Co-reporter:Aiping Chen, Ping Chen, Danyan Cao, Hui Lou
International Journal of Hydrogen Energy 2015 Volume 40(Issue 43) pp:14798-14805
Publication Date(Web):16 November 2015
DOI:10.1016/j.ijhydene.2015.09.030
•Aqueous phase reforming of low-boiling fraction is size sensitive.•With 1.6 nm Pt/Al2O3 as catalyst, 757 ml gas was produced and the selectivity of hydrogen reaches up to 65.86 vol.%.•The Pt atoms at vertexes and edges are active sites by providing stable Pt–C bonds and facilitating the cleavage of C–C bonds.Producing hydrogen through aqueous phase reforming (APR) of low-boiling fraction (LBF) which is obtained by distilling the crude bio-oil at reduced pressure is a promising way to categorize it as resource rather than waste. The catalytic conversion of renewable sources using catalyst with the best reactivity is essential to make the most of energy. The size effect of catalyst on APR of LBF has been studied. A series of γ-Al2O3 supported Pt nanoparticles catalysts with average sizes ranging from 1.6 nm to 5.7 nm were synthesized. The activity of this reaction and selectivity to hydrogen increased as the Pt particle size decreased. The full-shell cuboctahedron model was used to explain the phenomenon. It was proposed that the reaction activity and selectivity were size sensitive. Because particles with different size had different constitution of atoms and atoms at edges were the active sites for APR of LBF.
Co-reporter:Gang Feng, Zhen Liu, Ping Chen and Hui Lou
RSC Advances 2014 vol. 4(Issue 91) pp:49924-49929
Publication Date(Web):01 Oct 2014
DOI:10.1039/C4RA10891D
Solvents play a pivotal role in many chemical reactions as well as in upgrading of pyrolysis bio-oil. Herein we report a systematic study of the effects of solvents such as water, methanol, ethanol, propanol, butanol, acetone, ethyl acetate, tetrahydrofuran and hexane on hydrogenation of a lignin-derived component of pyrolysis bio-oil, phenol, over activated carbon supported palladium catalysts. The solvents were classified into four groups so as to better understand the effect of them. For hydrogen bond donor–hydrogen bond acceptor (HBD–HBA) solvents and hydrogen bond acceptor (HBA) solvents, the conversion of phenol decreased with increasing polarity/polarizability π*. Phenol was converted completely in hexane or water at 250 °C. However, in methanol or ethanol, it was converted partially. Synergistic action of multiple factors had an effect on the hydrogenation of phenol. To convert phenol better, water and hexane as solvents were excellent in upgrading of pyrolysis bio-oil.
Co-reporter:Yu Qin;Lili He;Jinzhao Duan;Dr. Ping Chen;Dr. Hui Lou;Dr. Xiaoming Zheng;Dr. Haiping Hong
ChemCatChem 2014 Volume 6( Issue 9) pp:2698-2705
Publication Date(Web):
DOI:10.1002/cctc.201402035
Abstract
The hydrodeoxygenation (HDO) of maize oil was performed in an autoclave with Mo-based catalysts supported by different carbon materials, such as reduced graphene oxide, activated charcoal, graphite, and fullerene. Nanostructured Mo-based catalysts with different phase compositions were prepared by using the carbothermal hydrogen reduction method at temperatures ranging from 500 to 700 °C and characterized by Raman spectroscopy, N2 adsorption isotherms, SEM, TEM, XRD, X-ray photoelectron spectroscopy, and ammonia temperature-programmed desorption. The highest total hydrocarbon yield of 90.32 % was obtained on the reduced graphene oxide-supported molybdenum carbide catalyst at 700 °C. These results are subject to the complicated effect of different factors such as phase composition, defect concentration, and particle size on the catalytic behavior of the materials. Unique structures of different supports also play a significant role in the HDO reaction. On the basis of the results of comprehensive analysis of products and catalysts, an HDO mechanism was proposed. These Mo-based catalysts are a promising system to prepare high-quality diesel fuels from renewable resources.
Co-reporter:Yu Qin, Ping Chen, Jinzhao Duan, Junxing Han, Hui Lou, Xiaoming Zheng and Haiping Hong
RSC Advances 2013 vol. 3(Issue 38) pp:17485-17491
Publication Date(Web):17 Jul 2013
DOI:10.1039/C3RA42434K
Carbon nanofiber-supported molybdenum carbide catalysts (Mo2C/CNF) with different loadings were prepared by the carbothermal hydrogen reduction method. Characterizations with Raman, XRD, N2-TGA, SEM, TEM and HAADF-STEM confirmed that Mo2C nanoparticles were successfully supported on the carbon nanofibers. The optimal reaction conditions with model compounds on Mo2C/CNF had a conversion of 98.03% and yield of 95.26%. It is interesting to note that a low evaporation rate positions the Mo2C nanoparticles on the outside of the CNF due to the capillary effect and the Mo2C nanoparticles on the outside of the CNFs showed high catalytic activity compared to ones on the inside of the CNFs. The Mo2C/CNF catalyst was recycled 5 times without any apparent loss of catalytic activity. Catalytic performances of Mo2C/CNF, Mo2C/AC (activated carbon) and Mo2C/CNT (multi-walled carbon nanotubes) were examined using methyl palmitate and maize oil. The results showed that molybdenum carbide could be a potential substitute for noble metals in transformation of vegetable oils.
Co-reporter:Dr. Junxing Han;Dr. Jinzhao Duan;Dr. Ping Chen; Hui Lou; Xiaoming Zheng;Dr. Haiping Hong
ChemSusChem 2012 Volume 5( Issue 4) pp:727-733
Publication Date(Web):
DOI:10.1002/cssc.201100476
Abstract
Ordered mesoporous carbon (OMC)-supported molybdenum carbide catalysts were successfully prepared in one pot using a solvent-evaporation-induced self-assembly strategy accompanied by a carbothermal hydrogen reduction reaction. Characterization with nitrogen sorption, small-angle XRD, and TEM confirmed that the obtained materials had high surface areas, large pore volumes, ordered mesoporous structures, narrow pore size distributions, and uniform dispersions of molybdenum carbide particles. With nitrogen replaced by hydrogen in the carbothermal reduction reaction, the formation temperature of molybdenum carbide could be reduced by more than 100 °C. By changing the amount of molybdenum precursor added from less than 2 % to more than 5 %, molybdenum carbide structures could be easily regulated from Mo2C to MoC. The catalytic performance of OMC-supported molybdenum carbide catalysts was evaluated by hydrodeoxygenation of vegetable oils. Compared with Mo2C, MoC exhibited high product selectivity and excellent resistance to leaching in the conversion of vegetable oils into diesel-like hydrocarbons.
Co-reporter:Junxing Han, Jinzhao Duan, Ping Chen, Hui Lou, Xiaoming Zheng and Haiping Hong
Green Chemistry 2011 vol. 13(Issue 9) pp:2561-2568
Publication Date(Web):29 Jul 2011
DOI:10.1039/C1GC15421D
Nanostructured molybdenum carbides supported on multi-walled carbon nanotubes (Mo2C/CNTs) with different loadings were prepared by carbothermal hydrogen reduction method and characterized with SEM, Raman, HAADF-STEM and XRD. Raman spectra showed that the specific G-band structure of carbon nanotubes promoted the formation of molybdenum carbide at lower temperatures. Compared with noble metals, molybdenum carbide exhibited better catalytic activity and resistance to leaching. The Mo2C/CNTs catalyst also showed high activity and selectivity for one-step conversion of vegetable oils into branched diesel-like hydrocarbons, which provided a promising approach to prepare high-grade diesel fuels from renewable resources.
Co-reporter:Junxing Han;Jinzhao Duan;Ping Chen;Xiaoming Zheng
Advanced Synthesis & Catalysis 2011 Volume 353( Issue 14-15) pp:2577-2583
Publication Date(Web):
DOI:10.1002/adsc.201100217
Abstract
In the paper, we report for the first time that the conversion of renewable oils into diesel-like hydrocarbon mixtures can be realized on molybdenum carbides with high activity and selectivity. The molybdenum carbide catalyst exhibited much better resistance to leaching than noble metals and could be reused consecutively for sixteen times without deactivation. Mechanism investigations indicated that molybdenum carbide and palladium showed different reaction selectivities and it was speculated that the level of difficulty in acyl-to-alkyl rearrangement of surface acyl intermediates on molybdenum carbide and palladium resulted in the different product selectivity.
Co-reporter:Junxing Han, Hui Sun, Yuqi Ding, Hui Lou and Xiaoming Zheng
Green Chemistry 2010 vol. 12(Issue 3) pp:463-467
Publication Date(Web):26 Jan 2010
DOI:10.1039/B917690J
An effective and highly selective decarboxylation approach to convert higher aliphatic esters into diesel-like paraffins has been developed. The results showed that palladium supported on barium sulfate was a potent catalyst to transform aliphatic esters into high-energy alkanes in supercritical hexane at a much lower temperature. Based on the comprehensive analysis to gas and liquid products, a decarboxylation mechanism was proposed. The methodology described in this paper provides a new protocol to the utilization of biomass-based resources, especially to the second generation biodiesel production.
Co-reporter:Junxing Han;Hui Sun;Jinzhao Duan;Yuqi Ding, ;Xiaoming Zheng
Advanced Synthesis & Catalysis 2010 Volume 352( Issue 11-12) pp:1805-1809
Publication Date(Web):
DOI:10.1002/adsc.201000195
Abstract
A size-controlled palladium nanoparticle catalyst prepared by adsorption of colloidal palladium nanoparticles on barium sulfate is efficient and highly selective in transforming vegetable oils into diesel-like fuel. Preliminary kinetic investigations using model compounds indicated that decarboxylation of aliphatic esters on palladium in a hydrogen-rich atmosphere showed a zero-order rate. Hydrogen temperature-programmed desorption measurements revealed that the high-temperature desorption of hydrogen species might be the rate-determining step.
Co-reporter:Jianjun Guo, Hui Lou, Liuye Mo, Xiaoming Zheng
Journal of Molecular Catalysis A: Chemical 2010 316(1–2) pp: 1-7
Publication Date(Web):
DOI:10.1016/j.molcata.2009.09.023
Co-reporter:Hui Sun, Kai Hu, Hui Lou and Xiaoming Zheng
Energy & Fuels 2008 Volume 22(Issue 4) pp:2756
Publication Date(Web):May 16, 2008
DOI:10.1021/ef700778r
The transesterification of rapeseed oil with methanol was carried out using a novel KF-loaded Eu 2O 3 catalyst. It was found that the catalyst with 15 wt % loaded KF and calcined at 873 K showed the optimum activity. X-ray diffraction (XRD), Fourier transform infrared (FTIR), CO 2-temperature-programmed desorption (TPD), and the Hammett titration method were employed for the catalyst characterization. The results showed that the activity of the catalysts was related with their basicity. The influence of various reaction variables on the conversion was also discussed. The mechanism for the formation of basic sites and the phase change of the KF-loaded Eu 2O 3 catalyst with different calcination temperatures is proposed.
Co-reporter:Zhen Liu, Wang Li, Chunyan Pan, Ping Chen, Hui Lou, Xiaoming Zheng
Catalysis Communications (15 November 2011) Volume 15(Issue 1) pp:82-87
Publication Date(Web):15 November 2011
DOI:10.1016/j.catcom.2011.08.019
A study of the liquid-phase conversion of biomass-derived sugars directly to methyl lactate catalyzed over solid base catalysts is presented. The yield of methyl lactate reached 29.45% under optimal reaction conditions. The effects of reaction time, reaction temperature, and catalysts calcination temperature were investigated. Fresh and used catalysts were characterized by XRD, CO2-TPD, and N2-adsorption techniques. MgO with the highest concentration of weakly basic sites was found to show the highest catalytic activity for the conversion of sugars to methyl lactate.Download full-size imageResearch Highlights► Biomass-derived sugars were used as feedstock. ► MgO calcined at 800 °C·min was found to be the one with highest catalytic activity. ► Methyl lactate could be separated easily from reaction mixture via distillation.
Co-reporter:Yuqi Ding, Hui Sun, Jinzhao Duan, Ping Chen, Hui Lou, Xiaoming Zheng
Catalysis Communications (10 March 2011) Volume 12(Issue 7) pp:606-610
Publication Date(Web):10 March 2011
DOI:10.1016/j.catcom.2010.12.019
Mesoporous 0.1M/ZrO2 (M = Li, Na, K, Mg, Ca) solid base catalysts were successfully synthesized by using a sol–gel method. The catalytic activities of the catalysts were tested via transesterification reactions of soybean oil with methanol. Both 0.1Mg/ZrO2 and 0.1Ca/ZrO2 catalysts showed no catalytic activity in this reaction, while Li, K modified ZrO2 catalysts achieved high yield of biodiesel production. Besides, under the optimum reaction conditions, a FAME yield of as high as 98.2% was achieved on 0.1Li/ZrO2 catalyst calcined at 650 °C.Download full-size imageResearch Highlights► Mesoporous 0.1M/ZrO2 (M=Li, Na, K, Mg, Ca) were synthesized by sol-gel method. ► High yields of biodiesel production were achieved on 0.1Li/ZrO2 and 0.1K/ZrO2. ► FAME yields on different catalysts were correlated to their basic properties.
Co-reporter:Gang Feng, Ping Chen and Hui Lou
Catalysis Science & Technology (2011-Present) 2015 - vol. 5(Issue 4) pp:NaN2304-2304
Publication Date(Web):2015/01/26
DOI:10.1039/C4CY01647E
Phenol is an important component of pyrolysis bio-oil, especially from lignin, and the conversion of phenol is crucial for the production of biofuel. A cost-effective and efficient catalyst is worth developing in the hydrogenation of phenol. Herein we report that supported palladium nanoparticles on carbon–nitrogen composites with high surface area are highly active for aqueous-phase hydrogenation of phenol. The conversion of phenol was 91.7% within 1 h at 80 °C. Higher activity was achieved at higher temperature. The synergy between palladium nanoparticles and the carbon–nitrogen composite support accelerated the hydrogenation of phenol, which clarified the crucial role played by the support. The hydrogenation of phenol highlights the potential of these catalysts for upgrading bio-oil.
