Armchair Janus WSSe Nanotube Designed with Selenium Vacancy as a Promising Photocatalyst for CO Reduction.

Photocatalytic conversion of carbon dioxide into chemical fuels offers a promising way to not only settle growing environmental problems but also provide a renewable energy source. In this study, through first-principles calculation, we found that the Se vacancy introduction can lead to the transition of physical-to-chemical CO adsorption on Janus WSSe nanotube. Se vacancies work at the adsorption site, which significantly improves the amount of transferred electrons at the interface, resulting in the enhanced electron orbital hybridization between adsorbents and substrates, and promising the high activity and selectivity for carbon dioxide reduction reaction (CORR). Under the condition of illumination, due to the adequate driving forces of photoexcited holes and electrons, oxygen generation reaction (OER) and CORR can occur spontaneously on the S and Se sides of the defective WSSe nanotube, respectively. The CO could be reduced into CH, meanwhile, the O is produced by the water oxidation, which also provides the hydrogen and electron source for the CORR. Our finding reveals a candidate photocatalyst for obtaining efficient photocatalytic CO conversion.