Effect of reduction temperature on Mo-based catalyst phase and its activity in hydrodeoxygenation reaction

doi:10.16085/j.issn.1000-6613.2016.05.027

Abstract

Abstract: A series of Mo-based catalysts supported over CNTs were successfully prepared by controlling the reduction temperature during the catalyst synthesis. The properties of the obtained catalysts were systematically characterized by XRD, TEM, N₂ adsorption, XPS and NH₃/H₂-TPD techniques, and the catalytic reactivity for the hydrodeoxygenation of stearic acid was evaluated. The results showed that Mo species on the surface of catalysts were reduced with the increase of reduction temperature, and the reduction process was as followed: MoO₃→MoO₂→Mo→Mo₂C. The active phase was MoO₂when reduction temperature was below 550℃. Further elevating the reduction temperature to 600℃, we found a mixed phase of MoO₂/Mo/β-Mo₂C existed. β-Mo₂C was the main active phase when reduction temperature was over 650℃, and it exhibited higher activity of hydrodeoxygenation than the active phase of MoO₂. In addition, the MoO₂/Mo/β-Mo₂C mixed phase catalyst at 600℃ showed the highest catalytic reactivity in hydrodeoxygenation of stearic acid due to its large specific surface area, more acid sites and stronger H₂ adsorption ability.

Key words: Mo-based catalyst, reduction, hydrogenation, reactivity

摘要： 以碳纳米管(CNTs)为载体,通过控制催化剂合成的还原温度制备了一系列负载型Mo基催化剂。采用XRD、TEM、N₂物理吸附、XPS以及NH₃/H₂-TPD等技术对催化剂进行了表征,并研究了Mo基催化剂对硬脂酸催化加氢脱氧性能的影响。结果表明:随着还原温度的升高,催化剂表面的Mo物种逐渐被还原,还原过程为:MoO₃→MoO₂→Mo→Mo₂C。还原温度为450℃和550℃时,催化剂的活性相为MoO₂;还原温度为600℃时,催化剂的活性相为MoO₂/Mo/β-Mo₂C的混合相;还原温度为650℃和700℃时,催化剂的活性相全部转化为β-Mo₂C。与活性相MoO₂催化剂相比,β-Mo₂C催化剂具有更高的加氢脱氧活性。此外,还原温度为600℃的MoO₂/Mo/β-Mo₂C混合相催化剂因具有较大的比表面积、较多的酸中心数量和较强的H₂吸附能力,使得该催化剂在硬脂酸加氢脱氧反应中表现出最优越的催化活性。

关键词: Mo基催化剂, 还原, 加氢, 活性

CLC Number:

LIANG Junmei, CHEN Yu, DING Ranran, MENG Yongqiang, WANG Yaowu, YANG Mingde, WU Yulong. Effect of reduction temperature on Mo-based catalyst phase and its activity in hydrodeoxygenation reaction[J]. Chemical Industry and Engineering Progree, 2016, 35(05): 1452-1459.

梁俊梅, 陈宇, 丁冉冉, 孟永强, 王要武, 杨明德, 吴玉龙. 还原温度对Mo基催化剂物相及其加氢脱氧性能的影响[J]. 化工进展, 2016, 35(05): 1452-1459.

References

[1] 黄付彬, 冯丽娟, 杨文超, 等. 藻类直接液化制取液体燃料研究进展[J]. 化工进展, 2012, 31(10): 2197-2201.
[2] ROZMYSLOWICZ B, MAKI-ARVELA P, TOKAREV A, et al. Influence of hydrogen in catalytic deoxygenation of fatty acids and their derivatives over Pd/C[J].Ind. Eng. Chem. Res., 2012, 51(26): 8922-8927.
[3] 赵永腾, 李涛, 徐军伟, 等. 微藻碳水化合物生产生物燃料的研究进展[J]. 化工进展, 2014, 33(4): 878-882.
[4] VARDON D R, SHARMA B K, SCOTT J, et al. Chemical properties of biocrude oil from the hydrothermal liquefaction of spirulina algae, swine manure, and digested anaerobic sludge[J].Bioresource Technol., 2011, 102(17): 8295-8303.
[5] CHEN Y, WU Y L, DING R R, et al. Catalytic hydrothermal liquefaction of D. tertiolecta for the production of bio-oil over different acid/base catalysts[J]. AIChE J., 2015, 61(4): 1118-1128.
[6] PENG B X, YAO Y, ZHAO C, et al. Towards quantitative conversion of microalgae oil to diesel-range alkanes with bifunctional catalysts[J]. Angew. Chem., 2012, 124(9): 2114-2117.
[7] ZOU S P, WU Y L, YANG M D, et al. Bio-oil production from sub-and supercritical water liquefaction of microalgae Dunaliella tertiolectaand related properties[J]. Energ. Environ. Sci., 2010, 3(8): 1073-1078.
[8] GOSSELINK R W, STELLWAGEN D R, BITTER J H. Tungsten-based catalysts for selective deoxygenation[J]. Angew. Chem., 2013, 125(19): 5193-5196.
[9] DING R R, WU Y L, CHEN Y, et al. Effective hydrodeoxygenation of palmitic acid to diesel-like hydrocarbons over MoO₂/CNTs catalyst[J]. Chem. Eng. Sci., 2014. DOI: 10.1016/j.ces.2014.10.024.
[10] HAN J X, DUAN J Z, CHEN P, et al. Nanostructured molybdenum carbides supported on carbon nanotubes as efficient catalysts for one-step hydrodeoxygenation and isomerization of vegetable oils[J]. Green Chem., 2011, 13(9): 2561-2568.
[11] WANG J, SHEN L F, DING B, et al. Fabrication of porous carbon spheres for high-performance electrochemical capacitors[J]. RSC Adv., 2014, 4(15): 7538-7544.
[12] LIU C C, LIN M G, JIANG D, et al. Preparation of promoted molybdenum carbides nanowire for CO hydrogenation[J]. Catal. Lett., 2014, 144(4): 567-573.
[13] GALADIMA A, ISMAIL A, ABDULLAHI I, et al. Supported molybdenum carbide as n-hexane upgrading catalyst[J]. Chem. Mat. Res., 2013, 3(11): 73-78.
[14] XIANG M L, LI D B, LI W H, et al. Potassium and nickel doped β-Mo₂C catalysts for mixed alcohols synthesis viasyngas[J]. Catal. Commun., 2007, 8(3): 513-518.
[15] ZHU Q L, ZHANG B, YANG J, et al. The promotion of nickel to Mo₂C/Al₂O₃catalyst for the partial oxidation of methane to syngas[J]. New J. Chem., 2003, 27(11): 1633-1638.
[16] XIANG M L, LI D B, XIAO H C, et al. K/Ni/β-Mo₂C: a highly active and selective catalyst for higher alcohols synthesis from CO hydrogenation[J]. Catal. Today, 2008, 131(1): 489-495.
[17] LI X Y, MA D, CHEN L M, et al. Fabrication of molybdenum carbide catalysts over multi-walled carbon nanotubes by carbothermal hydrogen reduction[J]. Catal. Lett., 2007, 116(1/2): 63-69.
[18] JIANG H, WANG L S, CUI W, et al. Study on the induction period of methane aromatization over Mo/HZSM-5: partial reduction of Mo species and formation of carbonaceous deposit[J].Catal. Lett., 1999, 57(3): 95-102.
[19] CHOI J S, BUGLI G, DJÉGA-MAIADASSOU G. Influence of the degree of carburization on the density of sites and hydrogenating activity of molybdenum carbides[J]. J. Catal., 2000, 193(2): 238-247.
[20] SUN Y M, HU X L, LUO W, et al. Ultrafine MoO₂ nanoparticles embedded in a carbon matrix as a high-capacity and long-life anode for lithium-ion batteries[J]. J. Mater. Chem., 2012, 22(2): 425-431.
[21] XIA F F, HU X L, SUN Y M, et al. Layer-by-layer assembled MoO₂-graphene thin film as a high-capacity and binder-free anode for lithium-ion batteries[J]. Nanoscale, 2012, 4(15): 4707-4711.
[22] MOON D J, RYU J W. Molybdenum carbide water-gas shift catalyst for fuel cell-powered vehicles applications[J]. Catal. Lett., 2004, 92(1/2): 17-24.
[23] CHEN H Y, CHEN L, LU Y, et al. Synthesis, characterization and application of nano-structured Mo₂C thin films[J]. Catal. Today, 2004, 96(3): 161-164.
[24] YANG Z H, CAI P J, SHI L, et al. A facile preparation of nanocrystalline Mo₂C from graphite or carbon nanotubes[J]. J. Solid State Chem., 2006, 179(1): 29-32.
[25] PERRET N, WANG X D, DELANNOY L, et al. Enhanced selective nitroarene hydrogenation over Au supported on β-Mo₂C and β-Mo₂C/Al₂O₃[J]. J. Catal., 2012, 286: 172-183.
[26] SOLYMOSI F, SZÉCHENYI A. Aromatization of n-butane and 1-butene over supported Mo₂C catalyst[J].J. Catal., 2004, 223(1): 221-231.
[27] FARKAS A P, SOLYMOSI F. Adsorption and reactions of ethanol on Mo₂C/Mo (100)[J]. Surf. Sci., 2007, 601(1): 193-200.
[28] 刘长城, 林明桂, 姜东, 等. Mg改性纳米线碳化钼在CO加氢反应中的应用[J]. 天然气化工(C1 化学与化工), 2014, 39(3): 36-41.
[29] EDAMOTO K, SUGIHARA M, OZAWA K, et al. Photoelectron spectroscopy study of oxygen adsorption on Mo₂C (0001)[J]. Surf. Sci., 2004, 561(1): 101-109.
[30] FLORES O G M, HA S. Activity and stability studies of MoO₂ catalyst for the partial oxidation of gasoline[J]. Appl. Catal. A: Gen., 2009, 352(1): 124-132.
[31] TORRES J, ALFONSO J E, LÓPEZ-CARREÑO L D. XPS and X-ray diffraction characterization of MoO₃ thin films prepared by laser evaporation[J]. Phys. Status Solidi(C), 2005, 2(10): 3726-3729.
[32] GAO S, LI G D, LIU Y P, et al. Electrocatalytic H₂ production from seawater over Co, N-codoped nanocarbons[J]. Nanoscale, 2015, 7(6): 2306-2316.
[33] GAO Q, ZHAO X Y, XIAO Y, et al. A mild route to mesoporous Mo₂C-C hybrid nanospheres for high performance lithium-ion batteries[J]. Nanoscale, 2014, 6(11): 6151-6157.
[34] 程新孙, 罗来涛, 鲁勋. Pd/ZrO₂-Al₂O₃催化剂加氢脱硫性能的研究[J]. 环境科学研究, 2008, 21(1): 139-144.
[35] DUAN Y N, WU Y L, ZHANG Q H, et al. Towards conversion of octanoic acid to liquid hydrocarbon via hydrodeoxygenation over Mo promoter nickel-based catalyst[J]. J. Mol. Catal. A: Chem., 2015, 398: 72-78.