Enhanced catalytic activity of CO2 hydrogenation to CO over sulfur-containing Ni/ZrO2 catalysts: support size effect

Abstract

Catalytic conversion of CO₂ to CO (reverse water-gas shift reaction, RWGS) is one of the most promising technologies for CO₂ resource utilization. In this work, a sulfur-containing zirconia supported nickel catalyst (Ni/ZrO₂) was prepared to improve the CO₂ conversion while adjusting the CO₂ hydrogenation selectivity from CH₄ to CO. The effect of support size (80 nm, 120 nm, 200 nm and 320 nm) on the catalytic performance of RWGS was investigated. The results showed that the Ni/ZrO₂-80 sample with a smaller support size of 80 nm exhibited higher Ni dispersion and oxygen vacancy concentration, which not only exposed more active sites but also enhanced the adsorption and activation capacity of CO₂. For these reasons, the CO₂ conversion of 27.6% with 100% selectivity of CO was achieved over Ni/ZrO₂-80, and no catalyst deactivation was observed during the stability test for 50 h. This work provides a new idea for designing the RWGS catalyst with an outstanding CO₂ hydrogenation performance.