Regenerable and durable catalyst for hydrogen production from ethanol steam reforming

摘要

In this work, perovskite-type oxides La_(1-x)Ca_xFe_(0.7)Ni_(0.3)O_3 were prepared by using a citrate complex method. The catalysts were employed in the reactions of steam reforming of ethanol (SRE) and oxidative steam reforming of ethanol (OSRE) to produce hydrogen. A reduction—oxidation cycle was proposed to overcome the problems of active component sintering and carbon deposition encountered in SRE reaction. In the ex-situ reactions, highly dispersed surface nickel particles formed during the reduction of La_(1-x)Ca_xFe_(0.7)Ni_(0.3)O_3, while during the introduction of an oxidative atmosphere these particles could be oxidized and restored back into the perovskite bulk. Owing to the existence of this segregation—incorporation cycle of nickel species in the perovskite oxides, the sintering of nickel particles under OSRE was found depressed effectively. Besides, this work proved that the oxygen in the feed is helpful to the elimination of deposited carbon. It seems promising for overcoming the problems of the active component sintering and carbon deposition in SRE reaction by regulating the redox ability of the perovskite-type oxides and the feed composition.