B-modified Pd/ZnAl2O4 Catalyst for Enhancing CO2 Hydrogenation to Methanol

Palladium (Pd)-based catalysts are widely used for CO 2 hydrogenation reactions due to the capability to activate H 2 , which enhances the overall CO 2 conversion. However, most of the current Pd catalysts reported show high CO 2 conversion only at higher temperature, and the exploration of efficient catalyst enabling low temperature conversion (180–300 °C) is of importance. In this study, a series of Pd-B/ZnAl 2 O 4 catalysts were synthesized via in-situ doping, resulting in the Pd crystal transformation induced from crystal to amorphous. The catalytic hydrogenation activity of the amorphous Pd-B catalyst reaches its zenith at a Pd-B mole ratio of 1:2, accompanied by the superior catalysis stability in CO 2 hydrogenation. Various characterization techniques, including XRD, CO-DRIFTS, H 2 -TPR, XPS and TEM, were used to investigate the properties of the Pd-B/ZnAl 2 O 4 catalyst. The results showed that the Pd-B/ZnAl 2 O 4 catalyst exhibited higher dispersion and better CO 2 conversion efficiency compared to unmodified Pd catalyst. Additionally, the methanol space–time yields are nearly doubled when the B decoration is employed. At 280 °C, CO 2 conversion was improved and methanol selectivity remained at ~ 65%. This study provides valuable insights into the design and optimization of Pd-B based catalysts for CO 2 hydrogenation at low temperatures. Graphical Abstract