In-plane heterojunctions enable multiphasic two-dimensional (2D) MoS₂ nanosheets as efficient photocatalysts for hydrogen evolution from water reduction

Journal Article · Fri Jan 01 00:00:00 EST 2016 · ACS Catalysis

DOI:https://doi.org/10.1021/acscatal.6b02076· OSTI ID:1327682

Peng, Rui ^[1]; Liang, Liangbo ^[1]; Hood, Zachary D. ^[2]; Boulesbaa, Abdelaziz ^[1]; Puretzky, Alexander ^[1]; Ievlev, Anton V. ^[1]; Come, Jeremy ^[1]; Ovchinnikova, Olga S. ^[1]; Wang, Hui ^[1]; Ma, Cheng ^[1]; Chi, Miaofang ^[1]; Sumpter, Bobby G. ^[1]; Wu, Zili ^[1]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Georgia Inst. of Technology, Atlanta, GA (United States)

Two-dimensional (2D) single-layer MoS₂ nanosheets are demonstrated as efficient photocatalysts for hydrogen evolution reaction (HER) from water reduction, thanks to specific in-plane heterojunctions constructed in the MoS₂ monolayer. These functional heterojunctions are formed among the different phases of chemically exfoliated MoS₂ monolayers: semiconducting 2H, metallic 1T, and quasi-metallic 1T' phases. The proportion of the three MoS₂ phases can be systematically controlled via thermal annealing of the nanosheets. Interestingly, a volcano relationship is observed between the photocatalytic HER activity and the annealing temperature with an optimum activity obtained after annealing at 60 °C. First-principles calculations were integrated with experimental studies to shed light on the role of the multiphases of MoS₂ and reveal that optimum photocatalytic HER activity results from the formation of the in-plane heterojunctions between 1T' MoS₂ and 2H MoS₂. Importantly, this facilitates not only balanced light absorption and charge generation by the 2H phase, efficient charge separation at the 1T'/2H interface, but also favorable HER over the basal sites of 1T' MoS₂. Furthermore, our work manifests how the confluence of the optical, electronic and chemical properties of 2D MoS₂ monolayers can be fully captured for efficient photocatalytic water reduction.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1327682
• Journal Information: ACS Catalysis, Vol. 6; ISSN 2155-5435
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

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36 MATERIALS SCIENCE