Bimetallic catalyst converts CO₂ to methanol

Capturing CO₂ from the air or from power-plant emissions and converting it to methanol sounds like a winning approach to curbing climate change. This strategy has the further benefit of being a potentially inexpensive way to make methanol, which is used as an industrial solvent and can double as a fuel or chemical reagent. But progress in driving CO₂ hydrogenation to methanol has been slow going. Some of the proposed methods are energy intensive and costly. Others produce a low concentration of methanol mixed with by-products. One of the leading catalyst candidates, a copper-zinc oxide system, generates methanol with low selectivity, and more importantly, it fails quickly because catalyst particles coalesce and block access to catalytically active sites. A team led by Jijie Wang, Guanna Li, and Can Li of the Dalian Institute of Chemical Physics reports that a “solid solution” of zinc oxide dispersed in a zirconium-oxide lattice is a more promising methanol synthesis catalyst (Sci. Adv. 2017, DOI: 10.1126/sciadv.1701290). The researchers find that ZnO-ZrO₂, which they prepare by reacting zinc nitrate and zirconium nitrate, generates methanol with up to 91% selectivity and retains its activity for more than 550 hours of reaction time, even in the presence of sulfur, a contaminant known to poison many solid catalysts. Computations indicate that the catalytic performance of the solid solution, which exceeds that of the individual components and physical mixtures of them, arises from the proximity of zinc and zirconium sites, which work in tandem to activate hydrogen.