posted on 2023-12-01, 15:07authored byEleonora Calì, Shailza Saini, Gwilherm Kerherve, William S. Skinner, Ian S. Metcalfe, David J. Payne, Kalliopi Kousi
The reforming reactions of greenhouse gases require catalysts
with
high reactivity, coking resistance, and structural stability for efficient
and durable use. Among the possible strategies, exsolution has been
shown to demonstrate the requirements needed to produce appropriate
catalysts for the dry reforming of methane, the conversion of which
strongly depends on the choice of active species, its interaction
with the support, and the catalyst size and dispersion properties.
Here, we exploit the exsolution approach, known to produce stable
and highly active nanoparticle-supported catalysts, to develop iridium-nanoparticle-decorated
perovskites and apply them as catalysts for the dry reforming of methane.
By studying the effect of several parameters, we tune the degree of
exsolution, and consequently the catalytic activity, thereby identifying
the most efficient sample, 0.5 atomic % Ir-BaTiO3, which
showed 82% and 86% conversion of CO2 and CH4, respectively. By comparison with standard impregnated catalysts
(e.g., Ir/Al2O3), we benchmark the activity
and stability of our exsolved systems. We find almost identical conversion
and syngas rates of formation but observe no carbon deposition for
the exsolved samples after catalytic testing; such deposition was
significant for the traditionally prepared impregnated Ir/Al2O3, with almost 30 mgC/gsample measured,
compared to 0 mgC/gsample detected for the exsolved
system. These findings highlight the possibility of achieving in a single step the mutual interaction of the parameters
enhancing the catalytic efficiency, leading to a promising pathway
for the design of catalysts for reforming reactions.