Oxidative dehydrogenation of ethane to ethylene over Ni–Nb–M–O catalysts: Effect of promoter metal and CO2-admixture on the performance

CATEGORY: OXIDATIVE DEHYDROGENATION
Oxidative dehydrogenation of ethane to ethylene over Ni–Nb–M–O catalysts: Effect of promoter metal and CO2-admixture on the performance

Type	Journal Article
Author	AiLing Qiao
Author	Venkata Narayana Kalevaru
URL	http://www.sciencedirect.com/science/article/pii/S0920586115005325
Series	Catalysis promoting the development of chemical industry: A special issue dedicated to Tianjin University’s 120th anniversary
Volume	264
Pages	144-151
Publication	Catalysis Today
Date	April 15, 2016
Abstract	Ni–Nb–O based catalysts have high activity and selectivity for the oxidative dehydrogenation of ethane (ODHE) to ethylene at relatively low temperatures. The parent Ni–Nb–O catalyst used in this work exhibited an ethylene yield of 32%. This solid was further modified by three promoters each, i.e. Cr, Mo, W, belonging to the same group of elements but exhibiting different d-characters. The purpose of such modification is to further improve activity and/or selectivity. However, the catalytic results of the doped solids revealed somewhat reduced activity compared to the parent Ni–Nb–O catalyst during ODHE. BET surface area data, reducibility, acidity characteristics as well as near-surface composition of Ni–Nb–M–O showed considerable deviations. However, these depend upon the nature of promoter doped. The near-surface region Ni/Nb ratio is the key parameter for tuning the catalytic properties of the solids. Among the three modifiers used, Cr displayed relatively superior catalytic performance compared to other two yielding in an ethane conversion of 26% and an ethylene selectivity of ca. 65%. Even so, the introduction of CO2-admixture into the reactant feed mixture improved the selectivity of ethylene in ODHE. Ni–Nb–Cr–O solid in particular revealed an enhanced ethylene selectivity of ca. 85% at slightly reduced ethane conversion.