Rationally Designed S-Scheme CeO/g-CN Heterojunction for Promoting Visible Light Driven CO Photoreduction into Syngas.

Exploring low-cost visible light photocatalysts for CO reduction to produce proportionally adjustable syngas is of great significance for meeting the needs of green chemical industry. A S-Scheme CeO/g-CN (CeO/CN) heterojunction was constructed by using a simple two-step calcination method. During the photocatalytic CO reduction process, the CeO/CN heterojunction can present a superior photocatalytic performance, and the obtained CO/H ratios in syngas can be regulated from 1 : 0.16 to 1 : 3.02. In addition, the CO and H production rate of the optimal CeO/CN composite can reach 1169.56 and 429.12 μmol g h, respectively. This superior photocatalytic performance is attributed to the unique S-Scheme photogenerated charge transfer mechanism between CeO and CN, which facilitates rapid charge separation and migration, while retaining the excellent redox capacity of both semiconductors. Particularly, the variable valence Ce/Ce can act as electron mediator between CeO and CN, which can promote electron transfer and improve the catalytic performance. This work is expected to provide a new useful reference for the rational construction of high efficiency S-Scheme heterojunction photocatalyst, and improve the efficiency of photocatalytic reduction of CO, promoting the photocatalytic reduction of CO into useful fuels.