Trinary nanohybrid nanocomposite (Ag/MoS2/ZnO): a plausible photoelectrode for photoelectrochemical water splitting

Abstract

The current study aims to synthesise a trinary nanohybrid composite (Ag/MoS₂/ZnO) and evaluate its potential applications as a photoanode for the production of hydrogen gas at low voltage (0.2 V vs. RHE). A combination of structural analysis via microscopy and elemental spectroscopy proved the success in integrating the Ag/MoS₂ dispersion phase onto the ZnO nanorod (ZnO NR) matrix. Optical characterization of the as-prepared Ag/MoS₂/ZnO indicates an improvement in light absorption in the visible light region, which benefits the photoelectrochemical process by creating additional photoexcitons. Analysis of photoelectrochemical performance reveals that the trinary nanohybrid composites exhibit better water-splitting efficiency than their single-component counterpart (ZnO). Among all the samples, 20 wt% Ag/MoS₂ depicts the best photoelectrochemical performance at a low onset potential (0.3 V vs. RHE) and photoconversion efficiency of 1.15% at a peak voltage of 0.85 V (vs. RHE). Without any externally supplied voltage, chronoamperometry measurements indicate a short circuit current of 0.70 mA cm⁻²; similar bias-free conditions can sustain self-driven hydrogen gas generation up to 54.49 μL according to gas chromatography analysis. The enhanced photoelectrochemical performance has been discussed and accredited to the presence of active edges in MoS₂ nanoflakes in addition to Ag nanoparticles, facilitating an efficient charge separation process. The current work can serve as a platform for exploring the potential of integrating compounds to realize bias-free water-splitting applications.