Optimization of an electrode made from CdS–ZnO nanorods for hydrogen generation from photoelectrochemical splitting of water

Nhat Hieu Hoang, Van Nghia Nguyen and Minh Thuy Doan

Abstract

Array structures of CdS-sensitized ZnO nanorods (NRs) were fabricated on conducting substrates of indium tin oxide (ITO) that serve as working electrodes in photoelectrochemical (PEC) cells for the generation of hydrogen by splitting of water. The ZnO NRs were synthesized by the hydrothermal method at low temperature with different growth times; structures of CdS-sensitized ZnO NRs were created by the dipping method with various dipping times to optimize the efficiency of splitting water. It was found that maximum photoconversion efficiency of an electrode made from CdS-sensitized ZnO NRs with a growth time of 3 h and a dipping time of 30 min under simulated solar irradiation of 100 mW cm⁻² was about 2.7%. The rate of evolution of H₂ gas generated from the water-splitting process was also measured. A maximum rate of 22 ml cm⁻² was achieved after 1 h exposure, which is higher than with CdS–ZnO NR electrodes in previous studies