Facile synthesis of an Ni/LaAlO3 – Perovskite via an MOF gel precursor for the dry reforming of methane

Abstract

A simple strategy to prepare the pure perovskite phase of lanthanum aluminate (LaAlO3) by calcination of a highly porous, dry MOF precursor gel has been developed. This study demonstrates that the structural and textural properties, such as specific surface area, pore volumes and pore sizes, of precursor-like metal–organic gels (MOG) (MOG-Al-La) based on metal–organic framework (MOF) structures can be modulated by optimizing the solvothermal treatment time. The perovskite obtained after solvothermal treatment at 120 °C for 12 h and calcination at 750 °C maintained the mesoporous characteristics of the MOF precursor, with a small particle size due to the decrease in crystallization temperature. These properties in the support allowed a good dispersion of the active Ni sites, low reducibility, and a strong interaction between them and the support, thus suppressing sintering under the severe catalytic reaction conditions evaluated (GHSV = 120,000 cm3/g·h) for the dry reforming of methane. The resulting MOX-(12 h)-LaAlO3-750-Ni catalyst gave a CH4 average conversion of 75% and CO2 average conversion of 80% after 20 h of reaction. The improved stability of the catalyst was attributed to suppression of the formation of the dense network of carbon filaments that can stress and subsequently fracture the support, cause attrition of the catalyst granules and hinder diffusion of the reactants both through the pores of the support and the interparticle spaces.