Characterization of Molybdenum Carbides for Methane Reforming by TPR, XRD, and XPS
摘要:
The relationship between various unsupported molybdenum carbides and their activity toward methane reforming at 973 K and 1 atm was studied. Unsupported molybdenum carbides catalyzed the formation of hydrogen in high selectivity, forming ethylene and ethane rather than benzene as the carbon-containing products. eta -Mo3C2, which was nitrided at 973 K and subsequently carbided at 1173 K, was more active than both alpha -MoC1-x and beta -Mo2C in methane decomposition, forming hydrogen in high selectivity. alpha -MoC1-x and gamma -Mo2N were transformed to eta -Mo3C2 in the bulk structure during methane reforming at 973 K. This transformation caused a significant increase in the turnover frequency of methane reforming. eta -molybdenum carbide was also formed during CH4-TPR Of gamma -Mo2N at 788 K. The linear relationship between the amount of il-carbide determined through H-2-TPR of the catalysts and the methane disappearance rate revealed that eta -Mo3C2 is the active species for methane reforming. From the XPS analysis, Mo-0 was the dominant molybdenum species for the eta -Mo3C2 catalysts.
On the preparation of molybdenum carbide-supported metal catalysts
作者:Joshua A. Schaidle、Neil M. Schweitzer、Olabode T. Ajenifujah、Levi T. Thompson
DOI:10.1016/j.jcat.2012.02.012
日期:2012.5
metal precursor complexes with unpassivated, high surface area Mo2C powders during wet impregnation. The rate of metal deposition and the final state of the metal were functions of the nature of the precursor (i.e., counter ion), electrostatic interactions, and red–ox reactions with the Mo2C surface. The deposition rate decreased in the following order: H2PtCl6 ∼ Pd(NH3)4(NO3)2 ∼ CuCl2 ∼ Cu(NO3)2 > C
(PEMFCs) running on hydrogen are attractive alternative power supplies for a range of applications, with in situ release of the required hydrogenfrom a stable liquid offering one way of ensuring its safe storage and transportation before use. The use of methanol is particularly interesting in this regard, because it is inexpensive and can reform itself with water to release hydrogen with a high gravimetric
Ethyl formate hydrogenolysis over Mo2C-based catalysts: Towards low temperature CO and CO2 hydrogenation to methanol
作者:Yuan Chen、Saemin Choi、Levi T. Thompson
DOI:10.1016/j.cattod.2015.08.021
日期:2016.1
the support suggesting some degree of cooperation between the Cu or Pd particles and the support. Temporal variations in rates for the Cu/Mo2C catalyst were consistent with first order kinetics with regard to ethyl formate and the activation energy was 44 kJ/mol. The best performance was achieved over a Pd-Cu/Mo2C catalyst; this material outperformed, by a significant margin, the oxide supported Cu
酯氢解是制备醇的关键步骤,并且正在寻求新的催化剂以改善该方法的性能和可持续性。本文所述的研究调查了使用Cu,Mo 2 C和Mo 2 N基催化剂在105–150°C和30 bar H 2的条件下对甲酸乙酯进行氢解。高表面积的基于Mo 2 C的催化剂比基于Mo 2 N的催化剂对甲醇更具活性和选择性。纳米级Cu和/或Pd颗粒在Mo 2 C或Mo 2上的沉积N显着提高了甲醇的选择性。甲醇的选择性随载体的酸度或碱度而变化,这表明Cu或Pd颗粒与载体之间存在一定程度的协同作用。Cu / Mo 2 C催化剂速率的时间变化与甲酸乙酯的一级动力学一致,活化能为44 kJ / mol。在Pd-Cu / Mo 2 C催化剂上获得了最佳性能;该材料的性能大大优于氧化物负载的Cu催化剂。Mo 2具有很高的活性和选择性,C负载的催化剂是酯氢解的有吸引力的候选者,包括低温期间的中间步骤,CO和CO 2的级联氢化为甲醇。
Crystal structure and morphology control of molybdenum carbide nanomaterials synthesized from an amine–metal oxide composite
作者:Cheng Wan、Nicole A. Knight、Brian M. Leonard
DOI:10.1039/c3cc46551a
日期:——
Multiple phases of molybdenum carbide have been synthesized using a unique amine–metal oxide composite material.
使用独特的胺-金属氧化物复合材料合成了多相钼碳化物。
Crystal-phase control of molybdenum carbide nanobelts for dehydrogenation of benzyl alcohol
Belt-shaped molybdenum carbides in α- and β-phases were synthesized by reducing and carburizing a nano-sized α-MoO3 precursor with hydrocarbon–hydrogen mixtures at appropriate temperatures; the β-Mo2C nanobelts with a higher fraction of coordinatively unsaturated Mo sites were more active than the α-MoC1−x nanobelts in dehydrogenation of benzyl alcohol to benzaldehyde.