Evaluating the Activity and Stability of Perovskite LaMO3-Based Pt Catalysts in the Aqueous Phase Reforming of Glycerol

Abstract

The aqueous phase reforming of glycerol, to hydrogen, alkanes and liquid phase dehydration/dehydrogenation products, was studied over a series of 1 wt% Pt/LaMO3 (where M = Al, Cr, Mn, Fe, Co, Ni) catalysts and compared to a standard 1 wt% Pt/γ-Al2O3 catalyst. The sol–gel combustion synthesis of lanthanum-based perovskites LaMO3 produced pure phase perovskites with surface areas of 8–18 m2g−1. Glycerol conversions were higher than the Pt/γ-Al2O3 (10%) for several perovskite supported catalysts, with the highest being for Pt/LaNiO3 (19%). Perovskite-based catalysts showed reduced alkane formation and significantly increased lactic acid formation compared to the standard catalyst. However, most of the perovskite materials undergo phase separation to LaCO3OH and respective M site oxides with Pt particle migration. The exception being the LaCrO3 support which was found to remain structurally stable. Catalytic performance remained stable over several cycles, for catalysts M = Al, Cr and Ni, despite phase separation of some of these materials. Materials where M site leaching into solution was observed (M = Mn and Co), were found to be catalytically unstable, which was hypothesised to be due to significant loss in support surface area and uncontrolled migration of Pt to the remaining support surface. In the case of Pt/LaNiO3 alloying between the exsoluted Ni and Pt was observed post reaction.

Identification of structural changes in CaCu3Ti4O12 on high energy ball milling and their effect on photocatalytic performance

“…For instance, structural features at the perovskite surface are known to significantly differ to that of the bulk. 34 (ii) Analysis of Cu oxidation state from Cu2p region is challenging due to small shifts in binding energy coupled with the broadness of the Cu 2+ 2p 3/2 peak.…”

La-Doped Alumina, Lanthanum Aluminate, Lanthanum Hexaaluminate, and Related Compounds: A Review Covering Synthesis, Structure, and Practical Importance

“…Emery et al performed a computational screening of perovskites for the solar-driven thermochemical splitting of water, resulting in 139 promising candidates. The potential of perovskite-derived catalysts (especially of those containing nickel) for syngas generation (i) by steam reforming of methane or tar, (ii) by CO 2 dry reforming of methane (DRM), , or (iii) by partial oxidation of methane (POM) has received much attention. ,− Perovskite-supported iridium was claimed as a catalyst for propellant decomposition in satellite thrusters…”