Self-gating in semiconductor electrocatalysis

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Self-gating in semiconductor electrocatalysis
Self-gating in semiconductor electrocatalysis
Journal Title:
Nature Materials
Publication Date:
22 July 2019
Nat. Mater. 2019, 18, 1098-1104
The semiconductor–electrolyte interface dominates the behaviours of semiconductor electrocatalysis, which has been modelled as a Schottky-analogue junction according to classical electron transfer theories. However, this model cannot be used to explain the extremely high carrier accumulations in ultrathin semiconductor catalysis observed in our work. Inspired by the recently developed ion-controlled electronics, we revisit the semiconductor–electrolyte interface and unravel a universal self-gating phenomenon through microcell-based in situ electronic/electrochemical measurements to clarify the electronic-conduction modulation of semiconductors during the electrocatalytic reaction. We then demonstrate that the type of semiconductor catalyst strongly correlates with their electrocatalysis; that is, n-type semiconductor catalysts favour cathodic reactions such as the hydrogen evolution reaction, p-type ones prefer anodic reactions such as the oxygen evolution reaction and bipolar ones tend to perform both anodic and cathodic reactions. Our study provides new insight into the electronic origin of the semiconductor–electrolyte interface during electrocatalysis, paving the way for designing high-performance semiconductor catalysts.
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Funding Info:
This work was supported by MOE under AcRF Tier 1 (M4011782.070 RG4/17 and M4011993.070 RG7/18), AcRF Tier 2 (2015-T2-2-007, 2016-T2-1-131, 2016-T2-2-153 and 2017-T2-2-136) and AcRF Tier 3 (2018-T3-1-002), and A*Star QTE programme. This work was also supported by MOE under AcRF Tier 2 (2015-T2-2-057, 2016-T2-2-103, 2017-T2-1-162) and AcRF Tier 1 (2016-T1-002-051, 2017-T1-001-150, 2017-T1-002-119), and NTU under Start-Up Grant (M4081296.070.500000) in Singapore. H.Z. thanks the support from ITC via Hong Kong Branch of National Precious Metals Material Engineering Research Center, and the Start-Up Grant from City University of Hong Kong. We would like to acknowledge the Facility for Analysis, Characterization, Testing and Simulation, Nanyang Technological University, Singapore, for use of their electron microscopy facilities. Q.J.W. acknowledges the support of the Ministry of Education- Singapore grant (MOE2016-T2-1-128) and National Research Foundation-Competitive Research Program (NRF-CRP18-2017-02). Z.W.S. acknowledges the support of the Institute of Materials Research and Engineering, A*STAR (IMRE/17-1R1211).
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