Photocatalytic ethane conversion on rutile TiO₂(110): identifying the role of the ethyl radical

Abstract

Oxidative dehydrogenation of ethane (C₂H₆, ODHE) is a promising approach to producing ethene (C₂H₄) in the chemical industry. However, the ODHE needs to be operated at a high temperature, and realizing the ODHE under mild conditions is still a big challenge. Herein, using photocatalytic ODHE to obtain C₂H₄ has been achieved successfully on a model rutile(R)-TiO₂(110) surface with high selectivity. Initially, the C₂H₆ reacts with hole trapped O_Ti^- centers to produce ethyl radicals , which can be precisely detected by a sensitive TOF method, and then the majority of the radicals spontaneously dehydrogenate into C₂H₄ without another photo-generated hole. In addition, parts of the radicals rebound with diversified surface sites to produce C₂ products <i>via</i> migration along the surface. The mechanistic model built in this work not only advances our knowledge of the C-H bond activation and low temperature C₂H₆ conversion, but also provides new opportunities for realizing the ODHE with high C₂H₄ efficiency under mild conditions.