Brookite TiO2quasi nanocubes decorated with Cu nanoclusters for enhanced photocatalytic hydrogen production activity

Abstract

Brookite TiO2quasi 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.