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2025 Vol.13, Issue 3 Preview Page
Atomic-Level Tuning of Photo-Assisted Electrodeposited Cobalt Phosphate Cocatalyst in Tailored Electrolyte for Enhanced n-Type BiVO4 Photoanodes
Kun Woong Lee1†
,
Dong Su Kim12†
,
Ye Sung Oh1
,
Hyung Koun Cho1*
1School of Advanced Materials Science and Engineering, Sungkyunkwan University, 2066, Suwon, 16419, Korea
2Department of Chemical & Biomolecular Engineering and Department of Chemistry, University of California, Berkeley, Energy Storage and Distributed Resources Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
†These authors equally contributed to this work.
*Corresponding Author
30 September 2025. pp. 132-141
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Abstract

Photoelectrochemical (PEC) water splitting is a promising green hydrogen production technology, but BiVO4-based photoanodes still face limited charge mobility and severe surface recombination. Here, BiVO4 thin films were precisely fabricated via a sol–gel process to optimize the trade-off between light absorption and hole diffusion length. Under neutral pH conditions, potassium phosphate buffer electrolyte exhibited low resistance and excellent oxygen evolution reaction activity, but its long-term stability remained insufficient. To address this, a CoPi cocatalyst was introduced using photo-assisted electrodeposition, promoting defect-selective and uniform CoPi growth. The resulting BiVO4/CoPi photoanode showed improved interfacial contact, achieving a high photocurrent density of 2.89 mA/cm2 and retaining 87.14% of its initial current after 10 hours. This study demonstrates a PEC photoanode design strategy that leverages synergistic interactions among the electrolyte, cocatalyst, and semiconductor, offering a promising approach for efficient and durable PEC water splitting systems capable of self-driven hydrogen production under real-world conditions.

Keywords
Photoelectrochemical
BiVO4 photoanode
CoPi cocatalyst
Near-neutral electrolyte
Oxygen evolution reaction
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Information
  • Publisher :Korea Photovoltaic Society
  • Publisher(Ko) :한국태양광발전학회
  • Journal Title :Current Photovoltaic Research
  • Volume : 13
  • No :3
  • Pages :132-141
  • Received Date : 2025-05-19
  • Revised Date : 2025-07-31
  • Accepted Date : 2025-08-07
  • DOI :https://doi.org/10.21218/CPR.2025.13.3.132
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