US EPA

4847132 

Journal Article 

MoS2/WS2 Heterojunction for Photoelectrochemical Water Oxidation 

Pesci, FM; Sokolikova, MS; Grotta, C; Sherrell, PC; Reale, F; Sharda, K; Ni, Na; Palczynski, P; Mattevi, C 

2017 

7 

8 

4990-4998 

10.1021/acscatal.7b01517 

WOS:000407309100009 

The solar-assisted oxidation of water is an essential half reaction for achieving a complete cycle of water splitting. The search of efficient photoanodes that can absorb light in the visible range is of paramount importance to enable cost-effective solar energy-conversion systems. Here, we demonstrate that atomically thin layers of MoS2 and WS2 can oxidize water to O-2 under incident light. Thin films of solution-processed MoS2 and WS2 nanosheets display n-type positive photocurrent densities of 0.45 mA cm(-2) and O-2 evolution under simulated solar irradiation. WS2 is significantly more efficient than MoS2; however, bulk heterojunctions (BHJs) of MoS2 and WS2 nanosheets results in a 10-fold increase in incident-photon-to-current-efficiency, compared to the individual constituents. This proves that charge carrier lifetime is tailorable in atomically thin crystals by creating heterojunctions of different compositions and architectures. Our results suggest that the MoS2 and WS2 nanosheets and their B-HJ blend are interesting photocatalytic systems for water oxidation, which can be coupled with different reduction processes for solar-fuel production. 

photoanode; water splitting; heterojunction; MoS2; WS2