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

Abstract

The selective hydrogenation of CO2 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 CO2 to dimethyl ether (DME) with a CO-free selectivity of about 80%. The activity of GaN for the hydrogenation of CO2 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 CO2 to DME and thus enriches the chemistry for CO2 transformations.

Recent Progress in Direct DME Synthesis and Potential of Bifunctional Catalysts

“…Gallium has already been used in various types of catalysts for methanol synthesis [96]. For example, in Ga 2 O 3supported Pd catalysts it is proposed that gallium oxide promotes CO 2 adsorption and Pd, similarly to the above mentioned effect in In 2 O 3 , catalyzes dissociation of H 2 , mechanistically resulting in hydrogen spill over to the oxide surface followed by the formation of formate [97].…”

Research progress of CO2 oxidative dehydrogenation of propane to propylene over Cr-free metal catalysts

“…Besides the common metal oxides, GaN constitutes another potential heterogeneous catalyst for oxidative dehydrogenation of propane [30,32,[117][118][119][120]. Inspired by the special strong local electrostatic polarization of GaN [121][122][123][124][125], recently, our group developed several GaNbased catalysts for C-H bond activation in the CO 2 -ODHP reaction [47,[126][127][128]. For example, Q-x (a type of SiO 2 supports with varying pore size) as supports to prepare GaN/Q-x catalysts which exhibited good to excellent catalytic activity and reusability in CO 2 -ODHP.…”

An atomistic insight into reactions and free-energy profiles of NH3 and Ga on GaN surfaces during the epitaxial growth

“…More generally, hydrogen has mainly been considered as a major player in catalysis processes [34] involved in GaN systems, without deepening the analysis into the implications for MOVPE produced GaN films. A deeper insight into the role of hydrogen in surface reconstruction and morphology of a growing GaN structure was proposed twenty years ago by van de Walle and Neugebauer [35] and, despite being a bit outdated, that work still represents one of the more reliable studies even nowadays.…”