Highly metallic Co-doped MoS2 nanosheets as an efficient cocatalyst to boost photoredox dual reaction for H2 production and benzyl alcohol oxidation

Developing appropriate cocatalyst to couple with photocatalyst is a promising strategy to simultaneously realize efficient benzyl alcohol oxidation to aldehydes and water reduction to H-2. Herein, two-dimensional (2D) Co-doped MoS2 nanosheets with an edge-enriched 1T phase were uniformly embedded onto 2D g-C3N4 (CN) nanosheets to fabricate a 2D/2D Co-doped MoS2/CH nano-junction, wherein the Co-doped MoS2, acting as a cocatalyst, can induce fast charge transfer and realize synchronously utilization of photo-electrons and photo-holes. The optimal Co-doped MoS2/CH nanojunction presented a high photocatalytic oxidation of benzyl alcohol with benzaldehyde generation rate of 0.48 mmol g(-1) h(-1) and photocatalytic reduction of water with H-2 generation of 0.31 mmol g(-1) h(-1). This greatly enhanced photocatalytic performance is attributed to the fact that the Co-doped MoS2, with an edge-enriched 1T phase as the cocatalyst, presented higher metallic characteristics, lower H* adsorption, and more active sites than the pure MoS2 cocatalyst. Additionally, the Codoped MoS2 cocatalyst and CN nanosheets formed a 2D/2D ohmic-junction with a chemical linkage (N-Mo-S-Co), providing a rapid charge transfer channel to accelerate charge transfer. This work replenishes a train of thought for the design of novel cocatalysts as a bridge for enhancing the H-2 production and value chemical production. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

In this study, a new type of cocatalyst with high photocatalytic activity was developed by embedding cobalt-doped MoS2 nanosheets onto 2D g-C3N4 nanosheets, which showed efficient benzaldehyde and H-2 generation rates. The enhanced photocatalytic performance was attributed to the metallic characteristics, lower H* adsorption, and active sites of the cobalt-doped MoS2 cocatalyst, as well as the rapid charge transfer facilitated by the 2D/2D ohmic-junction with a chemical linkage formed between the cocatalyst and CN nanosheets.