%0 Journal Article %@ 2574-0962 %A Alqahtani, M %A Sathasivam, S %A Alhassan, A %A Cui, F %A Benjaber, S %A Blackman, C %A Zhang, B %A Qin, Y %A Parkin, IP %A Nakamura, S %A Liu, H %A Wu, J %D 2018 %F discovery:10073811 %J ACS Applied Energy Materials %K indium gallium nitrides; quantum wells; photoelectrochemical water splitting; photoanodes; cobalt oxides %N 11 %P 6417-6424 %T InGaN/GaN Multiple Quantum Well Photoanode Modified with Cobalt Oxide for Water Oxidation %U https://discovery.ucl.ac.uk/id/eprint/10073811/ %V 1 %X Indium gallium nitride (InGaN) is an attractive semiconductor, with a tunable direct bandgap for photoelectrochemical water splitting, but it corrodes in aqueous electrolytes. Cobalt oxide (CoOx) is a promising cocatalyst to protect photoelectrodes and accelerate the charge transfer. CoOx is earth-abundant and stable in extremely alkaline conditions and shows high activity for the oxygen evolution reaction (OER). In this work, we demonstrate that CoOx directly deposited onto InGaN/GaN multiple quantum well photoanodes exhibits excellent activity and stability in a strong alkaline electrolyte, 1 M NaOH (pH = 13.7), for water oxidation up to 28 h, while a reference sample without the catalyst degraded rapidly in the alkaline electrolyte. Under simulated solar illumination, the CoOx-modified InGaN/GaN quantum well photoanode showed a high photocurrent density of 1.26 mA cm–2 at 1.23 V and an onset potential of −0.03 V versus a reversible hydrogen electrode. %Z This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions.