Gallium nitride catalyzed the direct hydrogenation of carbon dioxide to dimethyl ether as primary product

The selective hydrogenation of CO 2 to value-added chemicals is attractive but still challenged by the high-performance catalyst. In this work, we report that gallium nitride (GaN) catalyzes the direct hydrogenation of CO 2 to dimethyl ether (DME) with a CO-free selectivity of about 80%. The activity of GaN for the hydrogenation of CO 2 is much higher than that for the hydrogenation of CO although the product distribution is very similar. The steady-state and transient experimental results, spectroscopic studies, and density functional theory calculations rigorously reveal that DME is produced as the primary product via the methyl and formate intermediates, which are formed over different planes of GaN with similar activation energies. This essentially differs from the traditional DME synthesis via the methanol intermediate over a hybrid catalyst. The present work offers a different catalyst capable of the direct hydrogenation of CO 2 to DME and thus enriches the chemistry for CO 2 transformations. The conversion of CO 2 to valuable chemicals is still challenged by catalyst developments. Herein, the authors found that GaN is an efficient catalyst for selective CO 2 hydrogenation to dimethyl ether as the primary product, in contrast to the traditional methanol-intermediate route over hybrid catalysts.