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Near UV‐Irradiation of CuO x ‐Impregnated TiO 2 Providing Active Species for H 2 Production Through Methanol Photoreforming
Author(s) -
Vitiello Giuseppe,
Clarizia Laura,
Abdelraheem Wael,
Esposito Serena,
Bonelli Barbara,
Ditaranto Nicoletta,
Vergara Alessandro,
Nadagouda Mallikarjuna,
Dionysiou Dionysios D.,
Andreozzi Roberto,
Luciani Giuseppina,
Marotta Raffaele
Publication year - 2019
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201900818
Subject(s) - photocatalysis , catalysis , copper , x ray photoelectron spectroscopy , raman spectroscopy , materials science , calcination , high resolution transmission electron microscopy , hydrogen production , dissolution , methanol , inorganic chemistry , diffuse reflectance infrared fourier transform , transmission electron microscopy , nuclear chemistry , chemical engineering , chemistry , nanotechnology , metallurgy , organic chemistry , physics , optics , engineering
Copper doped‐TiO 2 (P25) nanomaterials have been intensively studied as promising catalysts for H 2 production by photo‐reforming of selected organic compounds. However, the role of copper oxidation states on the improvement of photocatalytic activity is still debated. In this work, CuO x ‐impregnated P25‐TiO 2 catalysts were used for photocatalytic production of hydrogen from methanol. Copper species/oxidation states both in the as‐prepared catalysts and after the photocatalytic process were investigated. To this purpose, H 2 production rates were correlated to physico‐chemical properties of the samples, both before and after photocatalytic process, by means of Raman, X‐Ray Diffraction, Electron Paramagnetic Resonance spectroscopy, X‐Ray Photoelectron Spectroscopy, Temperature‐Programmed Reduction and High Resolution Transmission Electron Microscope techniques. Results revealed the presence of both Cu 2 O and CuO deposits on the samples surface after calcination. Notably, under near‐UV irradiation, the fraction of highly dispersed CuO particles undergo a partial dissolution process, followed by reduction to metallic copper Cu (s) by photogenerated electrons, boosting H 2 production rate. Our findings indicate that both Cu 2 O and Cu (s) act as co‐catalysts for H 2 generation, yet by different mechanisms. Overall this study, provides the basis to enhance catalytic performance of red‐ox active systems through UV‐irradiation approach.