Induced C–C coupling in CO2 photocatalytic reduction via carbothermally reduced nonstoichiometric tungsten oxide

Li, T. and Dong, X. and Chen, W. and Zhao, X. and Li, G. and Feng, G. and Song, Y. and Wei, W. and Sun, Y.

Volume: 526 Pages:
DOI: 10.1016/j.apsusc.2020.146578
Published: 2020

Photocatalytic conversion of carbon dioxide (CO2) is a promising strategy for both renewable solar energy storage and carbon emission reduction. Forming multicarbon products in CO2 photocatalytic reduction remains very difficult, due to the kinetic barriers of C–C coupling. In this study, we introduce surface pentavalent tungstic (W5+) species in nonstoichiometric tungsten oxides via carbothermal reduction of commercial WO3 powder, achieving photocatalytic CO2 conversion with an aldehyde selectivity of 35% at a total normal CO2 conversion rate of 1.8 µmol·gcat−1·h−1. The as-prepared nonstoichiometric tungsten oxides exhibit improved band structures and electron transport properties, and the W5+ surface species with oxygen vacancies play a pivotal role in facilitating C–C coupling of key intermediates. In-depth carbothermal reduction at an elevated temperature (880 °C) delivers more tetravalent W4+ species, decreasing the CO and aldehyde production rates. This work provides fundamental information to facilitate C–C coupling in CO2 photoreduction via the introduction of surface active species. © 2020 Elsevier B.V.

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