Selective hydrogenation of acetylene to ethylene on anatase TiO2 through first-principles studies

Abstract

Titanium dioxide (TiO₂) alone is rarely reported to have exciting performance towards heterogeneous hydrogenation reactions. In this work, we demonstrate via density functional theory (DFT) calculations that anatase TiO₂ with oxygen vacancies (O_vs), which provides frustrated Lewis pairs (FLPs) from surface Ti and O atoms for the heterolytic dissociation of hydrogen, can effectively hydrogenate acetylene to ethylene. Meanwhile, the mechanisms of H₂ activation and acetylene hydrogenation with several structure–reactivity correlations are well established, suggesting the potential catalytic reactivity in the presence of O_vs on anatase TiO₂ surfaces. Then, the reactivity of anatase TiO₂ towards acetylene hydrogenation is preliminarily confirmed by experimental studies which show that the existence of O_vs after reduction leads to higher reactivity. These results can provide important implications for the further development of selective hydrogenation catalysts based on earth-abundant materials.