Understanding the Stability of Etched or Platinized p-GaInP Photocathodes for Solar-Driven H2 Evolution

Weilai Yu, James L. Young, Todd G. Deutsch, Nathan S. Lewis

Research output: Contribution to journalArticlepeer-review

6 Scopus Citations

Abstract

The long-term stability in acidic or alkaline aqueous electrolytes of p-Ga0.52In0.48P photocathodes, with a band gap of ∼1.8 eV, for the solar-driven hydrogen-evolution reaction (HER) has been evaluated from a thermodynamic, kinetic, and mechanistic perspective. At either pH 0 or pH 14, etched p-GaInP electrodes corroded cathodically under illumination and formed metallic In0 on the photoelectrode surface. In contrast, under the same conditions, electrodeposition of Pt facilitated the HER kinetics and stabilized p-GaInP/Pt photoelectrodes against such cathodic decomposition. When held at 0 V versus the reversible hydrogen electrode, p-GaInP/Pt electrodes in either pH = 0 or pH = 14 exhibited stable current densities (J) of ∼-9 mA cm-2 for hundreds of hours under simulated 1 sun illumination. During the stability tests, the current density-potential (J-E) characteristics of the p-GaInP/Pt photoelectrodes degraded due to pH-dependent changes in the surface chemistry of the photocathode. This work provides a fundamental understanding of the stability and corrosion mechanisms of p-GaInP photocathodes that constitute a promising top light absorber for tandem solar-fuel generators.

Original languageAmerican English
Pages (from-to)57350-57361
Number of pages12
JournalACS Applied Materials and Interfaces
Volume13
Issue number48
DOIs
StatePublished - 8 Dec 2021

Bibliographical note

Publisher Copyright:
© 2021 American Chemical Society.

NREL Publication Number

  • NREL/JA-5900-80102

Keywords

  • electrodeposition
  • hydrogen-evolution reaction
  • photoelectrode
  • semiconductor
  • tandem solar-fuel generators

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