Coral-like N-Doped Cd(O,S) Photocathodes with Oxygen Vacancies for Enhanced Hydrogen Generation

Abstract

Solar-driven hydrogen (H2) production is considered one of the most sustainable methods for clean energy generation to replace fossil fuel-based energy. Herein, we report a highly efficient 3D coral-like N-doped cadmium oxysulfide (Cd(O,S)) photocathodes for hydrogen evolution reaction (HER) in an alkaline solution. The N5-Cd(O,S) achieved an onset potential of 0.63 VRHE with a photocurrent density of 0.74 mA.cm-2 at 0 VRHE, and solar-to-hydrogen efficiency (hSTH) of 6.6 %. For practical application, the amount of evolved H2 by N5-Cd(O,S) photocathode was 12.3 mmol.cm-2 performed at 0 VRHE, improved 2-folds from Cd(O,S) without N dopant. Moreover, N5-Cd(O,S) exhibited excellent stability of 95.8 % for over 10 h HER testing. This work reveals that N5-Cd(O,S) photocathode can capture incident light efficiently with the 3D coral-like microstructure. In addition, the contained oxygen vacancies (OVs) in N5-Cd(O,S) play a dominant role for photoelectrochemical H2 generation.