Brookite TiO2 quasi nanocubes decorated with Cu nanoclusters for enhanced photocatalytic hydrogen production activity

Brookite TiO₂ quasi nanocubes (BTN) decorated with various Cu nanoclusters (CuNCs) contents (hereafter referred to as Cu/BTN composite) were synthesized via a facile chemical reduction process by NaBH₄. The obtained products and its Cu's existential state were characterized by X-ray diffraction, UV–Vis diffuse reflectance absorption spectroscopy, electron microscopy, X-ray photoelectron spectroscopy and X-ray fluorescence spectroscopy. It was found that the introduction of CuNCs with small size of ～1–2 nm on BTN surfaces can improve the photocatalytic H₂ production activity, and the maximum photoactivity (225 μmol h^?1) for H₂ production over 1.0 mol% Cu/BTN composite is similar to that (220 μmol h^?1) of the benchmark photocatalyst (P25) under the optimum photoreaction conditions, which is 5.2 times higher than that (42.5 μmol h^?1) of the BTN alone. This significant enhancement in the photoactivity of BTN is deemed to result from the metallic CuNCs with high surface area and dispersion, which favour the co-catalyst functions to cause an effective photogenerated carrier separation in space and an improvement in the photocatalytic activity and stability for H₂ production. The present results not only demonstrate the brookite TiO₂ would be a potential effective photocatalyst for H₂ production, but also provide an inexpensive, efficient and stable means of enhancing light-to-hydrogen energy conversion by using metallic Cu nanoclusters alternative to the commonly used noble metal co-catalyst.