Nanosheets of InS/S-CN-Dots for Solar Water-Splitting in Saline Water.

Hydrogen generation from splitting of water under the photoelectrochemical (PEC) pathway is considered as the most promising strategy for covering the upcoming fuel crisis by taking care of all environmental issues. In this context, InS can be explored as it is a visible light-active semiconductor with an appropriate band alignment with the water redox potential. Herein, InS nanosheets are developed by the chemical method. The nanosheets of InS absorb high visible light due to the manifold inside scattering and reflection. The PEC activity of InS is enhanced because of the increase in the light absorbance of the materials. In the present work, at 1.18 V RHE in 3.5 wt % NaCl, a maximum 2.07 mA/cm photocurrent density can be achieved by InS nanosheets. However, InS suffers strongly due to photo-corrosion. To improve the efficacy of the InS nanosheets in saline water, the charge-carrier transportation ability of InS is aimed to increase by decorating S-CN-dots on InS. The heterostructure of type-II is developed by sensitization of S-CN-dots on InS. It increases both the transportation of charge carriers as well as separation. In the heterostructure, the transient decay time (τ) increases, which indicates a decrease in photogenerated charge-carrier recombination. S-CN-dots also act as an optical antenna and increase the range of visible light absorbance of InS. The heterostructure can generate ∼2.38-fold higher photocurrent density of 1.18 V RHE in 3.5 wt % NaCl. The photoconversion efficiency of the heterostructure is 0.88% at 0.95 V RHE. The nanosheets of InS and InS/S-CN-dots are stable, and photocurrent density is measured up to 2700 s under continuous back-illumination conditions.