Hydrogen-substituted graphdiyne encapsulated cuprous oxide photocathode for efficient and stable photoelectrochemical water reduction
Xuedong Zhou, Baihe Fu, Linjuan Li, Z. Ryan Tian, Xiankui Xu, Zihao Wu, Jing Yang, Zhonghai Zhang
Abstract
Abstract Photoelectrochemical (PEC) water splitting is an appealing approach for “green” hydrogen generation. The natural p-type semiconductor of Cu 2 O is one of the most promising photocathode candidates for direct hydrogen generation. However, the Cu 2 O-based photocathodes still suffer severe self-photo-corrosion and fast surface electron-hole recombination issues. Herein, we propose a facile in-situ encapsulation strategy to protect Cu 2 O with hydrogen-substituted graphdiyne (HsGDY) and promote water reduction performance. The HsGDY encapsulated Cu 2 O nanowires (HsGDY@Cu 2 O NWs) photocathode demonstrates a high photocurrent density of −12.88 mA cm −2 at 0 V versus the reversible hydrogen electrode under 1 sun illumination, approaching to the theoretical value of Cu 2 O. The HsGDY@Cu 2 O NWs photocathode as well as presents excellent stability and contributes an impressive hydrogen generation rate of 218.2 ± 11.3 μmol h −1 cm −2 , which value has been further magnified to 861.1 ± 24.8 μmol h −1 cm −2 under illumination of concentrated solar light. The in-situ encapsulation strategy opens an avenue for rational design photocathodes for efficient and stable PEC water reduction.