Photocatalytic ethene synthesis from ethane dehydrogenation with high selectivity by ZnO-supported Pt nanoparticles

Abstract

Thermal catalytic oxidative dehydrogenation of ethane with O₂ has been extensively studied as an approach for ethene production, but this approach is energy intensive and has disadvantages of overoxidation, high-cost and safety concerns. Herein, we present ZnO-supported Pt nanoparticles that are highly active and selective for dehydrogenating ethane to ethene with simulated sunlight via a photo-supported Mars–van Krevelen mechanism. The Pt/ZnO catalyst achieves a high ethane-to-ethene conversion rate of 867.8 μmol h⁻¹ g⁻¹ and an excellent selectivity of 97.56%. Besides, it is also coking-resistant and can be readily revived by exposure to O₂ for refilling the consumed lattice oxygen to preserve its original activity. It is revealed that the Pt species facilitate C₂H₄ desorption from the catalyst to inhibit overoxidation and enhance separation of light-induced charges to boost the photocatalytic efficiency. Whilst the photogenerated holes on ZnO are captured by surface lattice oxygen to generate active O˙⁻ species, H atoms were extracted from adsorbed C₂H₆ to produce C₂H₄. In situ diffuse reflectance infrared Fourier transform spectroscopy is applied to detect the key intermediates and thus propose the possible catalytic EDH process over the Pt/ZnO photocatalyst.