Non-noble metals promoted MOF-derived CuZn catalysts for low-temperature CO2 hydrogenation to methanol

Abstract

In this work, CuZn-BTC-derived catalysts were modified with non-noble heterometals Ga, Ti, and Zr via an acidic etching self-assembly approach prior to calcination, yielding a series of heterometal-functionalized catalysts (CZB-Ga, CZB-Ti, and CZB-Zr) for CO<inf>2</inf> hydrogenation to methanol. A comparative characterization demonstrated that the addition of heterometals significantly improved the catalyst performance compared to the unmodified reference catalyst (CZB). The crystal characteristic of metal species (XRD and XPS) was dispersed on the surface and pore of the catalyst (N<inf>2</inf> physisorption and SEM), establishing correlations between physicochemical properties and catalytic behavior. Furthermore, the chemisorption analysis (N<inf>2</inf>O–, H<inf>2</inf>–, CO<inf>2</inf>-chemisorption, and H<inf>2</inf>-TPR analyses) confirmed that heterometal incorporation alters the surface chemical environment and enhances the dispersion of active sites. Among the modified catalysts, CZB-Ti exhibited superior performance under alcohol-assisted low-temperature conditions, achieving the highest CO<inf>2</inf> conversion (77.0 %) and methanol yield (12.2 %) under mild conditions (140–340 °C, 30 bar). The Ti-modified catalyst (CZB-Ti) was found to promote uniform dispersed active sites while concurrently suppressing undesired CO formation under low-temperature conditions. These findings highlight the critical role of non-noble heterometal functionalization in tailoring catalyst properties and enhancing the efficiency of CO<inf>2</inf> hydrogenation to methanol.