A particulate (ZnSe) 0.85 (CuIn 0.7 Ga 0.3 Se 2 ) 0.15 photocathode modified with CdS and ZnS for sunlight-driven overall water splitting

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2017, Vol.5 (40), p.21242-21248
• Main Authors: Goto, Yosuke, Minegishi, Tsutomu, Kageshima, Yosuke, Higashi, Tomohiro, Kaneko, Hiroyuki, Kuang, Yongbo, Nakabayashi, Mamiko, Shibata, Naoya, Ishihara, Hitoshi, Hayashi, Toshio, Kudo, Akihiko, Yamada, Taro, Domen, Kazunari
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/C7TA06663E

A photocathode prepared using the photocatalyst (ZnSe) 0.85 (CuIn 0.7 Ga 0.3 Se 2 ) 0.15 in powder form, and modified with CdS/ZnS overlayers and a Pt catalyst, exhibits a photocurrent of 4.3 mA cm −2 at 0 V RHE under AM 1.5G simulated sunlight. The photocathode was capable of utilizing photons up to 900 nm, while the onset potential was evaluated to be as high as 0.8 V RHE . Modification with thin CdS and ZnS layers significantly increases the cathodic photocurrent through the formation of a surface p–n junction. The half-cell solar-to-hydrogen conversion efficiency of 0.83% at 0.33 V RHE obtained from this device is among the highest yet reported for a photocathode fabricated from a particulate photocatalyst. A solar to hydrogen conversion efficiency of 0.60% was observed during bias-free overall water splitting using this photocathode together with a BiVO 4 photoanode. The present work clearly demonstrates the possibility of efficient hydrogen generation using durable particulate semiconductor photoelectrodes.