Enhanced photoelectrochemical water splitting in ternary layered chalcogenide ZnIn2S4 coupled with MWCNT

Abstract

Layered hexagonal zinc indium sulfide coupled with multiwalled carbon nanotubes (MWCNT/H-ZnIn₂S₄) nanocomposites were prepared via using the hydrothermal method and investigated its photoelectrochemical (PEC) water-splitting properties. A series of MWCNT/H-ZnIn₂S₄ nanocomposites with different concentrations of MWCNT have been synthesized. The effects of the addition of different concentrations of MWCNT on the PEC performance of H-ZnIn₂S₄ material are studied. The outcomes showed that the maximum value of photocurrent density is obtained for 20 wt% MWCNT/H-ZnIn₂S₄, which is ∼3.8 times higher as compared to the H-ZnIn₂S₄ photoanode under visible light illumination. The enhancement in the current density is because of the electron-accepting behavior of MWCNT that helps in the effective separation and transfer of charges at the interface. The ability of MWCNT to accept and transport electrons offers a better path to regulate the movement of photogenerated charge carriers, extending the lifetime of the photogenerated charges produced in the semiconductors. A plausible mechanism for observed enhanced PEC activity of MWCNT/H-ZnIn₂S₄ nanocomposites is provided, which is supported by impedance spectroscopy and Mott-Schottky results.