One-dimensional Au/SiC heterojunction nanocomposites with enhanced photocatalytic and photoelectrochemical performances: Kinetics and mechanism insights.

In this work, highly dispersed Au nanoparticles (NPs) decorated SiC nanowires (NWs) hybrids were firstly synthesized by a facile deposition-precipitation method. The as-prepared Au/SiC samples were characterized using various instrumental methods such as XRD, TEM, EDS, UV–vis DRS, BET, FTIR, XPS, PL, TRPL, and photoelectronchemical measurements. The solar H 2 production performances were investigated by using Na 2 S as sacrificial reagents in water under simulated sunlight illumination produced from a 300 W xenon lamp. Results showed that a significantly enhanced photoactivity for H 2 evolution (1495.8 μmol h −1 ·g −1 ) with apparent quantum efficiency (AQE) of 2.12% was achieved over the compostion-optimized Au/SiC composite (with 0.5 wt% Au), which was much higher than those of pure SiC NWs, Pt NPs deposited SiC NWs sample as well as the previously reported SiC-based catalysts. In cyclic tests, the AS0.5 showed acceptable photocatalytic stability and good structural stability. PL, TRPL and photoelectrochemical measurements disclosed that improved charge separation and retarded charge recombination were realized. However, the Au-loaded SiC products with strong surface plasmon resonance (SPR) absorption showed no activity for visible light photocatalytic H 2 production (λ ≥ 400 nm). Based on band-gap structures, the critical factors for SPR effect of Au NPs in activating or enhancing the visible-light photoactivities of semiconductors were proposed. This work can pave the avenue to the development of plasmonic metal decorated other narrow band gap semiconductors with plasmon-enhanced visible-light photoactivity for solar water splitting and related applications. [ABSTRACT FROM AUTHOR]