In this study, hydrogen gas (H2) and formic acid (HCOOH) are simultaneously generated through direct water photoelectrolysis and CO2 reduction, respectively, by using Ag nanoparticles (Ag NP) decorated n-GaN films as photoelectrodes. Photoelectrochemical cells with CO2-containing NaCl aqueous solution as an electrolyte and n-GaN films as photoelectrodes offer an environmentally friendly system to generate energy under sunlight. The typical production rates of HCOOH and H2 generated from the n-GaN photoelectrodes with TiO2/Ag NP composite layers are markedly higher than those for the n-GaN photoelectrodes without the TiO2/Ag NPs. The transmission spectra obtained from the TiO2/Ag NP/n-GaN photoelectrodes exhibited an additional visible light absorption band at around 550 nm due to localized surface plasmon resonance effect, except for the ultraviolet absorption with a wavelength of lower than 365 nm. However, the additional visible absorption was not the main cause of the enhancement of H2 and HCOOH production rates. Instead, the enhancement was mainly due to the remarkable improvement in texture at the photoelectrode/TiO2 interface.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films