Self‐Dispersing of (CuOx)n Species on Dark TiO2 Surface as a Key to High‐Performance HER Photocatalysts

Self-dispersion of polydisperse (CuO_x)_n nanoparticles obtained by pulsed laser ablation (PLA) to subnanometer CuO_x clusters and single atoms (SA) occurs on the surface of highly defective dark TiO₂ due to electrostatic interaction of differently charged DELs. The implementation of the SMSI effect between Ti³⁺ centers and Cu-containing particles with the participation of OH-groups of the support surface increases the AQY in HER to 55.3%.

Abstract

Advances in the development of photocatalytic hydrogen production are determined by the creation of technologies to synthesize highly active catalysts. In this work, a simple and effective approach to increasing the activity of defective dark TiO₂ in photocatalytic hydrogen evolution reaction (HER) is implemented, based on self-dispersing of (CuO_x)_n over the titania surface. The use of aggregated (CuO_x)_n clusters obtained by pulsed laser ablation, the presence of oxygen-deficient Ti³⁺ states in dark TiO₂ playing the role of an “anchor” to fix CuO_x clusters, and the presence of surface Ti⁴⁺–OH groups facilitating the production of atomically dispersed Cu species allow achieving high performance. The conditions of interaction between dark TiO₂ and (CuO_x)_n from simple mechanical mixtures to samples obtained by impregnation determine the state and dispersing of Cu-containing species on the catalyst surface and photocatalytic properties. The catalysts are studied by XRD, TEM, XPS, and UV–vis spectroscopy. The dispersing efficiency of (CuO_x)_n on the dark TiO₂ surface correlates with the increase in the AQY in photocatalytic HER. The maximum AQY of H₂ in a water-glycerol mixture under LED irradiation (λ = 375 nm) is 55.3%, which is comparable to the best results for the (CuO_x)_n-TiO₂ catalysts.

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