methylcyclopentane has been studied on tungstencarbide WC between 150 and 350°C. The experiments have been performed in a classical flow reactor under a great excess of hydrogen (pH2/pHC = 150) flowing at atmospheric pressure. The catalyst samples have been prepared in situ in the flow reactor system by reduction and carburization of WO3powder by a mixture of CH4(20%)/H2(80%) at T = 850°C for 4 h
2-甲基戊烷的氢解,Ñ己烷和甲基环戊烷已150和350℃之间研究了碳化钨WC。实验是在经典的流动反应器中在大气压下大量过量的氢气(p H 2 / p HC = 150)下进行的。所述催化剂样品已经制备原位在流动反应器系统中通过还原和渗碳WO 3粉末由CH的混合物4(20%)/ H 2在T = 850℃(80%)4小时。BET表面积约为12 m 2/G。这三种烃的反应主要产生裂化,随着温度升高,分子中碳原子越来越少。在T= 350℃下,仅观察到甲烷。由于骨架重排,异构化产物主要在低温下观察到,但它们仅占整个反应过程的百分之几。结果表明,在裂化反应领域中,碳化钨的催化性能接近钌,铱和镍等金属。
A family of oxide–carbide–carbon and oxide–nitride–carbon nanocomposites
作者:Z. Schnepp、M. J. Hollamby、M. Tanaka、Y. Matsushita、Y. Xu、Y. Sakka
DOI:10.1039/c3cc47480a
日期:——
This paper describes a powerful and versatile approach that combines the benefits of solâgel processing with controlled phase separation to yield oxideâcarbideâcarbon or oxideânitrideâcarbon nanocomposites.
Tungstencarbides were prepared by temperature-programmed reaction of WO3 with methane/hydrogen mixture and activated according to several thermal treatments by varying the temperature or the feed composition. Modification of these parameters was expected to change the surface composition (C/W). Such surface modifications have been related to acid–base properties observed in the decomposition of isopropanol
Epitaxial growth of WO3−x needles on (10 1̄0) and (01 1̄0) WC surfaces produced by controlled oxidation with CO2
作者:Andrew P. E. York、Jeremy Sloan、Malcolm L. H. Green、Jeremy Sloan
DOI:10.1039/a807403h
日期:——
The controlled oxidation with CO2 of both high surface area (high Sg) and low surface area WC to form WO3âx needles, has been observed in situ, inside a controlled environment transmission electron microscope (CETEM), and also ex situ, in a standard flow reactor; the tungsten oxide needles, which consist mainly of distorted γ-WO2.72, propagate in an epitaxial fashion from the (10 0) and (01 0) surfaces of the parent WC crystals; possible mechanisms for the formation of the needles are proposed.
Acid site densities and reactivity of oxygen-modified transition metal carbide catalysts
作者:Mark M. Sullivan、Aditya Bhan
DOI:10.1016/j.jcat.2016.09.012
日期:2016.12
Acidic properties of β-Mo2C, α-Mo2C, W2C, and WC were quantified by assessing the kinetics of isopropanol (IPA) dehydration at 415 K either (i) under inert He/Ar atmosphere or (ii) with 13 kPa O2 co-feed. Dehydration kinetics were zero-order with respect to IPA for all catalysts and under all reaction conditions. Intrinsic activation energies were similar across all catalysts (89–104 kJ mol−1). Acid