Stable and highly efficient MoS2/Si NWs hybrid heterostructure for photoelectrocatalytic hydrogen evolution reaction.

We report, the fabrication of molybdenum disulphide (MoS 2) wrapped silicon nanowires (Si NWs) for visible light driven water splitting applications. The morphological and elemental studies ensure the vertical alignment of Si NWs wrapped with 2D layered MoS 2. The photoelectrocatalytic (PEC) results evidence the significant enhancement in performance of MoS 2 /Si NWs based hybrid photocathode with ~300 mV (under reversible hydrogen electrode (RHE)) anodic shift in onset potential as that of pristine Si NWs (+0.194 V vs. RHE), and the current density of −26.5 mA/cm2 was achieved at the applied bias of 0 V vs. RHE. Further, the electrochemical impedance studies ensure the interface resistance-free charge transfer between Si NWs and electrolyte via 2D MoS 2 layer which provokes rapid hydrogen production. The wrapping of Si NWs with MoS 2 protects the superlative photocathode from harsh acid electrolyte environment. The overgrown MoS 2 triangular particles with active sulphur edge sites are found to eventually augment the solar hydrogen evolution rate. Further, the PEC performance of our MoS 2 /Si NWs is also comparable with stable Pt/Si NWs photoelectrode. It is note-worthy that, MoS 2 /Si NWs hybrid heterostructure would be a potential candidate in future large scale, low cost and day-to-day solar water splitting applications. Image 1 • MoS 2 /Si NWs hybrid heterostructure overcomes the limitation of standalone Si NWs. • It shows excellent PEC performance with the onset potential of +0.194V vs. RHE. • The heterostructure is expected to be the potential electrode for PEC applications. • Our MoS 2 /Si NWs device exhibits an excellent stability over 20,000 seconds. [ABSTRACT FROM AUTHOR]