Enhancement of photocatalytic and sonophotocatalytic hydrogen evolution over sensitized Ag/TiO₂

Abstract Photocatalysis is a promising technique for the production of hydrogen gas (H₂), which has high energy capacity. Investigations into raising the quantum yield of H₂ have considered the process itself and the compositions of the photocatalysts used. In particular, sensitization of semiconductors or their doping with metals has had a remarkable impact on the alternative energy industry. Dyes have great absorbance power under visible wavelengths, which overcomes a key limitation of TiO₂ as a semiconductor. In this research, cyanine derivatives connected with Ag/TiO₂ were characterized by XRD, SEM-EDX, TEM, and optical spectroscopy. The nanomaterials (48–88 nm) that were prepared had high crystallinity, and they were shifted to a region of sunlight radiation rich in photons, thereby enhancing the production of hydrogen. The improvement was more than by three-fold after 6 h. In addition, the combined light and ultrasound radiation yielded spectacular results, around six-fold of what was accomplished in the presence of light alone. Sonophotocatalysis has proven to be good for ensuring that particles do not aggregate during radiation and thus continue to produce abundant reactive oxidative species.