p-type Bismuth Vanadate for solar O₂ reduction to H₂O₂

Photoelectrochemical cells utilize solar energy to drive chemical reactions to produce fuels and chemicals. Oxide-based photoelectrodes are promising platforms due to their tunability and enhanced stability against photo-corrosion. While n-type oxide photoanodes like W- and Mo-doped BiVO₄ have been extensively studied, p-type oxides that can be used as photocathodes have received less attention. Recently, we investigated Ca-doped BiVO₄ as a p-type photocathode using a joint experimental-computational approach [1]. Our hybrid density functional theory (DFT) calculations revealed that Ca is an effective shallow acceptor dopant with low formation energy and thermal ionization energy leading to p-type conductivity via hole polarons. Our photoelectrochemical experiments then demonstrated that the Ca-doped BiVO₄ photocathode can be used for solar O₂ reduction to H₂O₂. In this work, we extend our investigation to additional p-type dopants, to understand the interplay between dopant size, site, and charge state. We also report dopant formation energies and thermal ionization energies and discuss their hole polaron transport properties, along with experimental validation.

[1] D. Seo, V. Somjit, et al. JACS 2025