Nb-Promoted Pt/MoOx/TiO2 Catalysts for Low-Temperature CO2 Hydrogenation to Methanol.

The catalytic hydrogenation of carbon dioxide (CO2) to methanol under mild conditions presents a sustainable route for carbon recycling and chemical energy storage. However, the inert nature of CO2 and high activation energy barrier for methanol formation remain major challenges. In this study, we developed a series of Nb-promoted Pt/MoOx/TiO2 catalysts for efficient CO2 hydrogenation at temperatures below 200 °C. Among these, Pt(5)/Mo(10)-Nb(1)/TiO2 exhibited superior performance, achieving a high methanol productivity of 3.8 mmol gcat -1 h-1 at 150 °C, outperforming the commercial Cu-ZnO/Al2O3 catalyst under comparable conditions. The catalyst showed stable performance during a 400 h long-term reaction. Detailed in situ and operando spectroscopic studies revealed that Pt sites were primarily responsible for H2 activation, while partially reduced MoOx species facilitated the formation of oxygenated intermediates. The incorporation of highly dispersed Nb species promoted methanol desorption and inhibited its decomposition, thereby contributing to the overall catalytic efficiency. This study outlines a rational design approach for constructing robust low-temperature catalysts and provides mechanistic insights into the synergistic roles of the metal and oxide components in CO2-to-methanol conversion.