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Boosting the photocatalytic hydrogen evolution performance via an atomically thin 2D heterojunction visualized by scanning photoelectrochemical microscopy

Cited 23 time in Web of Science Cited 26 time in Scopus
Authors

Lee, Jae Yoon; Kang, Sungwoo; Lee, Donghun; Choi, Seokhoon; Yang, Seunghoon; Kim, Kangwon; Kim, Yoon Seok; Kwon, Ki Chang; Choi, Soo Ho; Kim, Soo Min; Kim, Jihoon; Park, Jungwon; Park, Haeli; Huh, Woong; Kang, Hee Seong; Lee, Seong Won; Park, Hong-Gyu; Ko, Min Jae; Cheng, Hyeonsik; Han, Seungwu; Jang, Ho Won; Lee, Chul-Ho

Issue Date
2019-11
Publisher
Elsevier BV
Citation
Nano Energy, Vol.65, p. 104053
Abstract
Heterojunction catalyst can facilitate efficient photoelectrochemical (PEC) hydrogen evolution by reducing a potential barrier for charge transfer at the semiconductor/electrolyte interface. Such a heterojunction effect at the atomic thickness limit has not yet been explored although it can be strengthened because of strong built-in field and ultrafast charge transfer across the junction. Here, we first investigate a novel strategy to boost the hydrogen evolution performance of the p-type WSe2 photocathode via reducing the overpotential with an atomically thin heterojunction catalyst comprising MoS2 and WS2 monolayers. To unveil an effective role of the heterojunction by isolating its kinetic contribution from other collective catalytic effects, we develop and utilize an in situ scanning PEC microscopy, which enables the spatially-resolved visualization of the enhanced photocatalytic hydrogen evolution performance of the heterojunction. Notably, significant reduction in overpotential, from +0.28 +/- 0.03 to -0.04 +/- 0.05 V versus (vs.) the reversible hydrogen electrode (RHE), is achieved when the MoS2/WS2 heterojunction is introduced as a catalyst even without intentional generation of catalytic sites. As a result, the photocurrent of similar to 4.0 mA cm(-2) occurs even at 0 V vs. RHE. Furthermore, the beneficial effect of the atomically scaled vertical heterojunction is explained by the built-in potential resulted from efficient charge transfer in type-II heterojunctions with the support of first-principles calculations. Our demonstration not only offers an unprecedented approach to investigating the fundamental PEC characteristics in relation to the tailored properties of a catalyst but also proposes a new catalytic architecture, thereby enabling the design of highly efficient PEC systems.
ISSN
2211-2855
URI
https://hdl.handle.net/10371/191494
DOI
https://doi.org/10.1016/j.nanoen.2019.104053
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  • College of Engineering
  • Department of Electrical and Computer Engineering
Research Area 2차원 반도체 소자 및 재료, 뉴로모픽 소자 및 응용기술, 저전력 소자 및 소자물리

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