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

•In situ photodeposition of zero-valent nano copper on TiO2-P25.•Assessment on the efficient system nano-copper/TiO2-P25/UV–vis for H2 evolution.•Evaluation of the system behavior using different organic sacrificial agents.•Depiction of a H2 generation mechanism based on localized surface plasmon resonance.

Hydrogen production through the photoreforming of organic species using copper-modified TiO2 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 TiO2-P25 was used as starting material for the photocatalyst preparation, while CuSO4 and Cu2O were alternatively added to TiO2-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 CuSO4 and Cu2O together with TiO2-P25. Furthermore, a mechanism of hydrogen generation based on localized surface plasmon resonance (LSPR) was proposed.

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