Long-term solar water and CO2 splitting with photoelectrochemical BiOI-BiVO4 tandems

Virgil Andrei; Robert A Jagt; Motiar Rahaman; Leonardo Lari; Vlado K Lazarov; Judith L MacManus-Driscoll; Robert L Z Hoye; Erwin Reisner

doi:10.1038/s41563-022-01262-w

Long-term solar water and CO₂ splitting with photoelectrochemical BiOI-BiVO₄ tandems

Nat Mater. 2022 Aug;21(8):864-868. doi: 10.1038/s41563-022-01262-w. Epub 2022 May 26.

Authors

Virgil Andrei^#^{1

2}, Robert A Jagt^#³, Motiar Rahaman¹, Leonardo Lari⁴, Vlado K Lazarov⁴, Judith L MacManus-Driscoll⁵, Robert L Z Hoye⁶, Erwin Reisner⁷

Affiliations

¹ Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK.
² Optoelectronics Group, University of Cambridge, Cavendish Laboratory, Cambridge, UK.
³ Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, UK.
⁴ Department of Physics, University of York, Heslington, York, UK.
⁵ Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, UK. jld35@cam.ac.uk.
⁶ Department of Materials, Imperial College London, London, UK. r.hoye@imperial.ac.uk.
⁷ Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK. reisner@ch.cam.ac.uk.

^# Contributed equally.

PMID: 35618828
DOI: 10.1038/s41563-022-01262-w

Abstract

Photoelectrochemical (PEC) devices have been developed for direct solar fuel production but the limited stability of submerged light absorbers can hamper their commercial prospects.^1,2 Here, we demonstrate photocathodes with an operational H₂ evolution activity over weeks, by integrating a BiOI light absorber into a robust, oxide-based architecture with a graphite paste conductive encapsulant. In this case, the activity towards proton and CO₂ reduction is mainly limited by catalyst degradation. We also introduce multiple-pixel devices as an innovative design principle for PEC systems, displaying superior photocurrents, onset biases and stability over corresponding conventional single-pixel devices. Accordingly, PEC tandem devices comprising multiple-pixel BiOI photocathodes and BiVO₄ photoanodes can sustain bias-free water splitting for 240 h, while devices with a Cu₉₂In₈ alloy catalyst demonstrate unassisted syngas production from CO₂.