2D SnS₂-CNT nanocomposite photoelectrode for enhanced photoelectrochemical water splitting performance

Tin-sulphide (SnS₂) nanosheets coupled with carbon nanotube (CNT) have been synthesized with different proportions of CNT (5 wt %, 10 wt %, and 20 wt %) to investigate their properties for photoelectrochemical (PEC) water-splitting applications. Microscopic studies revealed that the nanosheets of SnS₂ are uniformly dispersed on CNT. SnS₂ and SnS₂/CNT nanocomposite photoanodes were fabricated using the spray coating method for photoelectrochemical studies. Under similar light illumination, the current density of SnS₂/CNT-10 nanocomposite photoanode is ∼8.5 times higher compared to SnS₂ photoanode at 1.0 V vs Ag/AgCl. The enhancement in PEC performance is attributed to the conducting nature of CNT and the larger band bending induced by CNT. The CNT conducting network facilitates the effective transfer of charge carriers. Also, the electron-accepting nature of CNT helps to improve the overall PEC performance by lowering the rate of recombination of charge carriers. Further, the presence of sulphur vacancies in SnS₂/CNT nanocomposite prolongs the life of photogenerated charge carriers, improves its separation efficiency, and provides more surface-active sites for electrochemical reactions. A potential explanation for observed enhancement is provided and supported by electrochemical impedance spectroscopy (EIS) and Mott-Schottky results. These results highlight the substantial potential of SnS₂/CNT nanocomposites for photoelectrochemical water-splitting applications.