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

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. A supported metal catalyst such as Ni/Al2O3 is
known to catalyse 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 in 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 the 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 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 weak acid
centres in the 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
a correlation between the product distribution, nature of coke deposited,
and reforming temperature, as well as the type of support and structural
modification. Hence, the integration of a robust perovskite material as a
catalyst promoter and choice of support could be tailored in the 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.