Unlocking the positive effect of non-polar ZnO facets in ZrZnOx catalysts for CO2 hydrogenation

Abstract

A pivotal aspect in advancing ZrZnO_x catalysts for CO₂ hydrogenation lies in the modulation of Zr-O-Zn active sites, with ZnO facets emerging as potential modulators of site activity. Whereas the beneficial influence of non-polar ZnO facets on ZrZnO_x catalysts has been scarcely documented. Our investigation reveals that ZrZnO_x catalysts exposed non-polar ZnO facets (ZrZnO-n) exhibit superior methanol selectivity (74 %) compared to those with randomly exposed ZnO facets (ZrZnO-r, 35 %). Characterization results demonstrate that it is ascribed to the formation of highly active Zr-O-Zn^(2−δ)+ sites on ZrZnO-n, which facilitate H₂ adsorption and dissociation. In situ spectroscopic studies and DFT calculations further substantiate this finding, demonstrating enhanced intermediates formation and more efficient hydrogenation processes. This research underscores the significance of ZnO facet engineering in the purposeful creation of efficient ZrZnO_x catalysts for CO₂ hydrogenation.