BiVO4 photoanodes enhanced with metal phosphide co-catalysts: relevant properties to boost photoanode performance

Junyi Cui, Matyas Daboczi, Zhenyu Cui, Mengjun Gong, Joseph Flitcroft, Jonathan Skelton, Stephen C. Parker, Salvador Eslava

Research output: Contribution to journalArticlepeer-review

Abstract

Achieving highly performant photoanodes for oxygen evolution is key to developing photoelectrochemical devices for solar water splitting. In this work, we enhance BiVO4 photoanodes with a series of core-shell structured bimetallic nickel-cobalt phosphides (MPs) and provide key insights into the role of co-catalysts. The best BiVO4/Ni1.5Co0.5P and BiVO4/Ni0.5Co1.5P photoanodes achieved a 3.5-fold increase in photocurrent compared with bare BiVO4. We discovered that this enhanced performance arises from a synergy between work function, catalytic activity, and capacitive ability of the MPs. Distribution of relaxation times analysis reveals that the contact between the MPs, BiVO4 and the electrolyte gives rise to three routes for hole injection into the electrolyte, all of which are significantly improved by the presence of a second metal cation in the co-catalyst. Kinetic studies demonstrate that the significantly improved interfacial charge injection is due to a lower charge-transfer resistance, enhanced OER kinetics, and larger surface hole concentrations, providing deeper insights into
the carrier dynamics in these photoanode/co-catalyst systems for their rational design.
Original languageEnglish
Article number2306757
JournalSmall
Volume20
Issue number7
Early online date6 Oct 2023
DOIs
Publication statusPublished - 15 Feb 2024

Keywords

  • Nickel cobalt phosphides
  • BiVO4 photoanodes
  • bimetallic cocatalysts
  • synergistic effect
  • IMPS-DRT analysis
  • DFT calculations

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