Abstract
Semiconductor/metal hybrid nanostructures-based finely tuning the charge transfer as a promising approach has been identified for photocatalytic activity recently towards renewable hydrogen (H2) evolution reaction (HER) and environmental remediation. Engineering surface-active facets of the metal cocatalyst on the surface of 3-dimensional (3D) structured photocatalysts not only efficiently promotes charge separation and transfer but also serves as reaction active sites for the further development of advanced photocatalysts. Herein, taking 3D SrTiO3 (STO) as a model, we introduce a plasmonic photocatalyst involving the adjusted loading of well-defined Ag active components as a cocatalyst deposited on the surface of 3D STO nanocubes to form the binary Ag/STO nanostructures for photocatalytic behavior driven by light at wavelengths of 365 nm and 420 nm. After the incorporation of the functional cocatalyst, the photocurrent response of STO was substantially increased, while its photoluminescence emission significantly declined, which could be due to the Schottky channel and enrichment of surface reactants: (i) the enhancement of the interfacial separation and inhibition of the recombination process of the photogenerated electron-hole pairs; and (ii) the Ag arrangement on the 3D structure could not only promote the enhanced light absorption but also provide a large surface area with highly active sites for the photocatalytic reaction. The as-synthesized hybrid photocatalyst with a loading content of 1 wt% Ag displays a high photocatalytic H2 evolution and RhB degradation reaching 30 mu mol g-1 h-1 (H2 gas) and a rate constant (k) of 0.027 min-1 (RhB dye), which was 2.5, and 3.4 times higher than that of the pristine STO specimen (12.5 mu mol g-1 h-1 and k = 0.008 min-1, respectively, at 385 nm). Under a wavelength of 420 nm, the binary Ag/STO structures exhibited excellent performance for the H2 production (17.5 mu mol g-1 h-1) and RhB degradation (k = 0.0134 min-1) in comparison with the pristine STO specimen. They also demonstrated remarkable stability for H2 evolution and dye degradation performance in continuous cycles. Based on the experimental outcomes, an energy band outline and a plausible mechanism have been proposed to describe the charge transfer and separation process for enhanced HER activity and RhB degradation.
NSTL
Elsevier