In situ photodeposited nanoCu on TiO2 as a catalyst for hydrogen production under UV/visible radiation

Hydrogen production through the photoreforming of organic species using copper-modified TiO<inf>2</inf> photocatalysts is attracting a considerable attention. In particular, the use of catalysts, prepared by in situ photodeposition processes, with nanometric sizes could represent a straightforward promising strategy to improve the process efficiency. In this study, a nanometric TiO<inf>2</inf>-P25 was used as starting material for the photocatalyst preparation, while CuSO<inf>4</inf> and Cu<inf>2</inf>O were alternatively added to TiO<inf>2</inf>-P25 aqueous suspension before the irradiation.The behavior of different alcohols and organic acids to undergo photoreforming with hydrogen production was investigated and compared. A characterization of the catalysts recovered at the end of the runs was performed by Raman and electron paramagnetic resonance spectroscopy, UV-visible diffuse reflectance and X-ray diffractometry. Experimental results clearly indicate the formation of zero-valent copper nanoparticles on the catalysts surface, when employing both CuSO<inf>4</inf> and Cu<inf>2</inf>O together with TiO<inf>2</inf>-P25. Furthermore, a mechanism of hydrogen generation based on localized surface plasmon resonance (LSPR) was proposed.