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Investigations of the stability of etched or platinized p-InP(100) photocathodes for solar-driven hydrogen evolution in acidic or alkaline aqueous electrolytes

Yu, Weilai and Richter, Matthias H. and Buabthong, Pakpoom and Moreno-Hernandez, Ivan A. and Read, Carlos G. and Simonoff, Ethan and Brunschwig, Bruce S. and Lewis, Nathan S. (2021) Investigations of the stability of etched or platinized p-InP(100) photocathodes for solar-driven hydrogen evolution in acidic or alkaline aqueous electrolytes. Energy & Environmental Science, 14 (11). pp. 6007-6020. ISSN 1754-5692. doi:10.1039/d1ee02809j.

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The stability of p-InP photocathodes performing the hydrogen-evolution reaction (HER) has been evaluated in contact with either 1.0 M H₂SO₄ (aq) or 1.0 M KOH(aq), with a focus on identifying corrosion mechanisms. Stability for the solar-driven HER was evaluated using p-InP electrodes that were either etched or coated with an electrodeposited Pt catalyst (p-InP/Pt). Variables such as trace O₂ were systematically controlled during the measurements. Changes in surface characteristics after exposure to electrochemical conditions as well as electrode dissolution processes were monitored using X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma mass spectrometry (ICP-MS). In either H₂SO₄ or KOH, etched p-InP photoelectrodes corroded cathodically under illumination, forming metallic In⁰ at the electrode surface. In contrast, electrodeposition of Pt kinetically stabilized illuminated p-InP photocathodes in both H₂SO₄ and KOH by inhibiting the cathodic corrosion pathway. Notably, when held at 0 V vs. the reversible hydrogen electrode (RHE) in 1.0 M H₂SO₄ (aq), p-InP/Pt exhibited a stable current density (J) of ∼−18 mA cm⁻² for >285 h under simulated 1 Sun illumination. The long-term current density vs. potential (J–E) behavior at pH 0 and pH 14 of p-InP/Pt photocathodes correlated with changes in the surface chemistry as well as the dissolution of p-InP. In acidic media, the J–E behavior of p-InP/Pt photocathodes remained nearly constant with time, but the surface of a p-InP/Pt electrodes gradually turned P-rich via a slow and continuous leaching of In ions. In alkaline electrolyte, the surface of p-InP/Pt electrodes was passivated by formation of an InO_x layer that exhibited negligible dissolution but led to a substantial degradation in the J–E characteristics. Consequently, changes in the catalytic kinetics and surface stoichiometry are both important considerations for determining the corrosion chemistry and the long-term operational stability of InP photoelectrodes.

Item Type:Article
Related URLs:
URLURL TypeDescription Information
Yu, Weilai0000-0002-9420-0702
Richter, Matthias H.0000-0003-0091-2045
Buabthong, Pakpoom0000-0001-5538-138X
Moreno-Hernandez, Ivan A.0000-0001-6461-9214
Simonoff, Ethan0000-0002-2156-8602
Brunschwig, Bruce S.0000-0002-6135-6727
Lewis, Nathan S.0000-0001-5245-0538
Additional Information:© The Royal Society of Chemistry 2021. Submitted 09 Sep 2021; Accepted 23 Sep 2021; First published 30 Sep 2021. This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the office of Science of the U.S. Department of Energy under Award Number DE-SC0004993 and under award DE-SC0022087 from the Basic Energy Sciences Office of the DOE. Research was in part carried out at the Molecular Materials Resource Center (MMRC) of the Beckman Institute of the California Institute of Technology. W. Yu and C. G. Read acknowledge the Resnick Sustainability Institute (RSI) at Caltech for fellowship support. I. A. Moreno-Hernandez acknowledges a National Science Foundation Graduate Research Fellowship (Grant No. DGE-1144469). Prof. Dr Hans-Joachim Lewerenz, Dr Ke Sun and Dr Chengxiang Xiang are gratefully acknowledged for inspiring discussions. Dr Kimberly M. Papadantonakis is thanked for assistance with manuscript editing. Dr Nathan Dalleska is thanked for assistance with ICP-MS analyses. Ryan Jones is acknowledged for assistance with the design of the compression cell. Sean Byrne and Heng Dong are acknowledged for assistance with experiments. There are no conflicts to declare.
Group:JCAP, Resnick Sustainability Institute
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0004993
Department of Energy (DOE)DE-SC0022087
Resnick Sustainability InstituteUNSPECIFIED
NSF Graduate Research FellowshipDGE-1144469
Issue or Number:11
Record Number:CaltechAUTHORS:20211117-163656680
Persistent URL:
Official Citation:Investigations of the stability of etched or platinized p-InP(100) photocathodes for solar-driven hydrogen evolution in acidic or alkaline aqueous electrolytes. Energy Environ. Sci., 2021,14, 6007-6020; DOI: 10.1039/d1ee02809j
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:111916
Deposited By: Tony Diaz
Deposited On:17 Nov 2021 17:20
Last Modified:17 Nov 2021 17:20

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