Perovskite modified catalysts with improved coke resistance for steam reforming of glycerol to renewable hydrogen fuel

Abstract

Catalytic steam reforming of renewable feedstock to renewable energy or chemicals always goes with intense coking activities that produce carbonaceous products leading to low performance and eventual catalyst deactivation. Supported metal catalyst such as Ni/Al2O3 is known to catalysed gasification and decomposition of biomass feedstock largely for renewable fuel production with promising results. Catalyst deactivation from high carbon deposition, agglomeration and phase transformations resulting to rapid deactivation are some of the issues identified with the use of the catalyst. In this work, improvement on the coke resistance and catalytic properties of Ni/Al2O3 catalyst is sought via the use of a thermally stable and coke-resistant perovskite La0.75Sr0.25Cr0.5Mn0.5O3-δ (LSCM) as catalyst promoter/modifier and involving Zirconia-doped Ceria (Ce-Zr) as alternative support in steam reforming of pure and by-product glycerol. The stabilizing influence of the LSCM on the Ni catalyst has improved stability against agents of deactivation with a consequent significant improvement of catalytic activity of Ni/Al2O3 in H2 production and robust suppression of carbon deposition. Particularly, the synergy between the LSCM promoter and alternative Ce0.75Zr0.25O2 support enhanced the basic and redox properties known for Ce0.75Zr0.25O2 support in contrast to the week acid centres in γ-Al2O3 support which further improved nickel stability, catalyst–support interaction with a resultant high catalytic activity and robust coke suppression as a result of enhanced oxygen mobility. There is correlation between the product distribution, nature of coke deposited and reforming temperature as well as type of support and structural modification. Hence, integration of a robust perovskite material as a catalyst promoter and choice of support could be tailored in design and development of robust catalyst systems to improve the performance of supported metal catalysts, particularly the suppression of carbon deposition for hydrocarbon and biomass conversion to renewable fuel or chemicals.