MoSe<sub>2</sub> nanosheets/SiNWs heterojunction-based photocathode for efficient photoelectrochemical water splitting applications
Rahul, Sweta Sharma, Pooja Devi, S. K. Arora
Abstract
Abstract The efficiency of a photoelectrochemical (PEC) device is governed by the solar response of the photoelectrode and kinematics of the hydrogen evolution reaction (HER). In this study, we illustrate a simple and low-cost method for the fabrication of photocathode (PC) via spray coating of MoSe 2 nanosheets (prepared by liquid exfoliation) on p-SiNWs (p-type Silicon nanowires (NWs) prepared using metal-assisted chemical etching technique) and studied their integration as a PC for photoelectrochemical-hydrogen evolution reaction performance. The colossal photocurrent density of the resultant p-SiNWs-MoSe 2 PC is −14.56 mA cm −2 at −1.2 V, which is appreciably larger in comparison to the bare p-SiNWs. Moreover, the charge transfer resistance ( R ct ) corresponding to the p-SiNWs-MoSe 2 electrode is 339 Ω, which is about two orders of magnitudes lower than that of p-SiNWs is attributed to the high donor density of MoSe 2 nanosheets. The improvement in PEC performance is attributed to the strain at the p-SiNWs-MoSe 2 interface promoted charge separation and thus reduces the kinetic barrier in water splitting process and enhances the overall HER. These results open up a scalable and effective route for implementing solar-fuel conversion at a large scale.