Renewable syngas & hydrogen synthesis via steam reforming of glycerol over ceria-mediated exsolved metal nano catalysts

Abstract

Currently, catalyst design and development has drawn much attention as results of its strategic importance in the area of energy applications particular those involving biomass conversion. This work tailored exsolution of metal catalysts through the use of ceria for enhanced structural and catalytic behaviour in steam reforming of glycerol. Aside the understanding that defects due to A-site deficiency facilitates formation of vacant sites and exsolution of metal catalysts on the B-site of perovskite systems, this work has exemplified that metals such as ceria significantly influences the exsolution and general morphological surface architecture and catalytic behaviour. The exsolved nickel catalysts anchored and socketed on a titanate support and the ceria's basic surface properties and oxygen storage-release behaviour has modified the perovskite surface chemistry and enhanced catalytic behaviour particularly deactivation due to carbon deposition and reusability. Other exsolvable dopant metal species such as Fe and Co forms alloys with nickel on the surface and the synergy between the dopant metals in the alloy yielded better results. Furthermore, in one of the catalyst systems, the most commonly observed tolerable A-site deficiency and doping limit of 2% known for SrTiO3 perovskite was overstretched by 0.5% (2.5%) thereby increasing the defect chemistry. The catalyst system with such formulation has shown a dramatic exsolution phenomenon and catalytic behaviour and robust suppression of coke deposition. CO selectivity >60% and H2 selectivity >40% was recorded with all the catalyst systems. The catalysts used in this work are useful for applications in energy and production of value added chemicals.