2D/2D heterojunction of SnS2/g-C3N4 nanocomposite photoelectrode for improved photoelectrochemical water splitting performance

Abstract

This work presents the synthesis of photoelectrode composed of tin disulfide (SnS2) coupled with graphitic carbon nitride (g-C3N4) to improve the efficiency of photoelectrochemical (PEC) water splitting. The SnS2/g-C3N4 nanocomposite was prepared using the chemisorption process, and the photoelectrode was prepared of thin film deposited on fluorine-doped tin oxide (FTO) substrate employing the spray coating technique. Photocurrent density for SnS2/g-C3N4-20 nanocomposite is ∼ 1.0 mA/cm2 at 1.0 V versus the Ag/AgCl reference electrode, which is ∼ 5 times the value for pristine SnS2 photoelectrode. The maximum PEC performance is achieved for 20 wt% of g-C3N4 in SnS2/g-C3N4-20 nanocomposite. The incident photon-to-current conversion efficiency (IPCE) value of the SnS2/g-C3N4 −20 nanocomposite exhibits an enhancement of ∼ 4.3-fold compared to bare SnS2. This enhancement in PEC performance can be due to type-II heterojunction formed at the interface of SnS2 and g-C3N4, which facilitates efficient charge separation and reduces recombination losses. This enhanced photocurrent density is supported by Mott-Schottky studies and electrochemical impedance spectroscopy (EIS) results. This work elucidates the significant potential of SnS2/g-C3N4 heterostructures as efficient and durable photoelectrodes for renewable hydrogen production, contributing towards the advancement of sustainable energy technologies.