Gold-palladium bimetallic nanoalloy decorated ultrathin 2D TiO2 nanosheets as efficient photocatalysts with high hydrogen evolution activity

In this work, a novel AuPd bimetallic nanoalloy decorated ultrathin 2D titanium dioxide (TiO2) nanosheet with high H-2 evolution activity was prepared via a facile in situ synthesis method. The physical and photophysical properties of the as-prepared AuPd/TiO2 nanosheets were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-visible diffuse reflection spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), electron spin resonance (ESR) and surface photocurrent spectroscopy (SPC). The photocatalytic H-2 evolution experiments indicate that the AuPd co-catalysts can efficiently promote the separation of photogenerated charge carriers in TiO2, and consequently enhance the H-2 evolution activity. The 0.3 wt% AuPd/TiO2 sample shows the highest catalytic activity, and the corresponding H-2 evolution rate is 526 mu mol h(-1) g(-1), which is 31 times higher than that of pure TiO2 under simulated sunlight (mu > 300 nm) irradiation. A possible mechanism of the enhanced simulated sunlight catalytic performance of AuPd bimetallic nanoparticle (NP) decorated TiO2 nanosheets is proposed to guide further improvement of desirable functional materials. It is expected that the AuPd decorated TiO2 nanosheets obtained via a simple synthesis approach can be used as efficient photocatalysts and exhibit promising potential for new energy applications.