Ultrafine Pt Nanoparticles on Defective Tungsten Oxide for Photocatalytic Ethylene Synthesis.

The selective conversion of ethane (C 2 H 6 ) to ethylene (C 2 H 4 ) under mild conditions is highly wanted, yet very challenging. Herein, it is demonstrated that a Pt/WO 3-x catalyst, constructed by supporting ultrafine Pt nanoparticles on the surface of oxygen-deficient tungsten oxide (WO 3-x ) nanoplates, is efficient and reusable for photocatalytic C 2 H 6 dehydrogenation to produce C 2 H 4 with high selectivity. Specifically, under pure light irradiation, the optimized Pt/WO 3-x photocatalyst exhibits C 2 H 4 and H 2 yield rates of 291.8 and 373.4 µmol g -1  h -1 , respectively, coupled with a small formation of CO (85.2 µmol g -1  h -1 ) and CH 4 (19.0 µmol g -1  h -1 ), corresponding to a high C 2 H 4 selectivity of 84.9%. Experimental and theoretical studies reveal that the vacancy-rich WO 3-x catalyst enables broad optical harvesting to generate charge carriers by light for working the redox reactions. Meanwhile, the Pt cocatalyst reinforces adsorption of C 2 H 6 , desorption of key reaction species, and separation and migration of light-induced charges to promote the dehydrogenation reaction with high productivity and selectivity. In situ diffuse reflectance infrared Fourier transform spectroscopy and density functional theory calculation expose the key intermediates formed on the Pt/WO 3-x catalyst during the reaction, which permits the construction of the possible C 2 H 6  dehydrogenation mechanism.