Hydrogen Generation of Cu2O Nanoparticles/MnO–MnO2 Nanorods Heterojunction Supported on Sonochemical-Assisted Synthesized Few-Layer Graphene in Water-Splitting Photocathode

In this study, we investigated the production of hydrogen by photochemical water splitting. A multi-shaped Cu 2 O nanoparticles/MnO–MnO 2 nanorods heterojunction on a few-layer graphene-based electrode serves as the photocathode. Multi-shaped Cu 2 O nanoparticles, including truncated cubic shape, cuboctahedral shape, truncated octahedral shape, and octahedral shape, were then coated on square manganese nanorods on a few-layer graphene-based electrode as the photosensitizer. Finally, the efficiency of hydrogen production was measured and recorded. The Cu 2 O nanoparticles/MnO–MnO 2 nanorods heterojunction generates photoelectrons to reduce hydrogen ions into hydrogen gas. The manganese dioxide nanorods were combined with cuprous oxide multi-shaped nanoparticles to be simultaneously utilized in hydrogen production as a photochemical water-splitting solar cell. The highest rate of hydrogen generation is 33.0 mL/min m 2 under solar simulation radiation. This study highlights the significance of a back electron–hole recombination loss and transportation process on the surface of a water-splitting photocathode, retarding the appearance of the photocurrent and requiring a greater amount of energy from a solar device.