Fine-tuning B-site of a Chromite based Perovskite Catalyst for Steam Reforming of Glycerol
- PDF / 1,300,860 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 64 Downloads / 279 Views
Fine-tuning B-site of a Chromite based Perovskite Catalyst for Steam Reforming of Glycerol Ahmed Umar1 and John T.S. Irvine2 1 School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK 2 School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK ABSTRACT The perovskite catalysts La0.75Sr0.25Cr0.5X0.5O3±δ (where X= Mn, Fe and Co) were prepared by combustion synthesis and the influence of transition metals B-site substitution on the structural and catalytic properties of the catalysts in steam reforming of both pure and by-product glycerol to produce hydrogen-rich gases for utilization in solid oxide fuel cell was investigated. All the catalyst systems were found very active and selective with the Fe-substituted catalyst slightly more active. Hydrogen yield and coke suppression was better in the Mn-substituted catalyst which was also structurally more stable in fuel environment. Impregnation of Ni into the lattice structure of the pre-reacted both A-site and B-site stoichiometric catalysts from nickel nitrate solution and subsequent redox exsolution of Ni nano particles supported on the oxide surface of the materials has significantly improved the hydrogen yield by enhancing water-gasshift reaction (WGSR). Thus, extent of the exsolution phenomenon observed in the materials followed the order LSCM > LSCC > LSCF.
INTRODUCTION Biomass feedstock such as by-product glycerol which is currently in surplus is renewable and an enviably intense energy resource for sustainable hydrogen generation for utilization in fuel cell [1]. However, use of glycerol feedstock and other large hydrocarbon leads to catalyst deactivation due to coking [1]. Incorporating transition metals into the B-site of perovskite particularly the chromite-based has been reported to have potential for improving its catalytic properties in methane reforming, coke suppression and stability in fuel environment [2]. Furthermore, synthesis of oxide supported metal particles catalyst by metal impregnation/deposition or assembling techniques is time consuming, costly and difficult to control particle size, growth and distribution. It also offers only weak interaction between the active phase metal particles and support resulting in agglomeration, instability and deactivation, hence offers poor catalytic properties [1,3] Alternatively, the exsolution method reduces time and condition of processing, cheap and provides plausible control over particle size, growth and distribution, it also offers strong interaction between metal and the oxide support hence gives enhanced catalytic properties [4]. In this, an attempt is made to investigate the influence of some selected substituted metals on the structural and catalytic properties of a highly doped (50%) Bsite chromium-based La0.75Sr0.25Cr0.5X0.5 O3±δ (X=Mn, Fe and Co) perovskites catalyst in steam reforming of glycerol. In addition, influence of nickel impregnation into lattice structure of the pre-reacted metal substituted catalysts on catalytic activity
Data Loading...
