Tuning of the morphological and electronic properties of In2S3 nanosheets by cerium ion intercalation for optimizing photocatalytic activity

Abstract

In this work, a facile hydrothermal treatment has been followed to develop In₂S₃ nanosheets doped with 0–2 mol% cerium. Morphological and structural analyses have revealed the development of highly crystalline smooth In₂S₃ nanosheets upon 1 mol% cerium doping. The substitutionally doped cerium ions have led to hybridization of the Ce 4f and In 5p orbitals resulting in downshift of the conduction band edge thus aiding in higher photon absorption for enhanced photocatalytic activity. Such characteristics have been deduced from the UV-vis spectra and further theoretically verified by employing first principles density functional theory (DFT) calculations to obtain density of states (DOS) plots of computationally constructed 1 mol% Ce doped In₂S₃ structures. Transient photocurrent responses have been obtained and photocatalytic degradation of neurotoxic drug ciprofloxacin has been performed to demonstrate the enhanced photocatalytic and photoelectrocatalytic potential of cerium doped samples. The marked improvement showed a rapid decline in the 2 mol% Ce doped samples, due to the limited solubility of cerium ions in the In₂S₃ lattice leading to structural deformities upon excess cerium doping. Thus, the synergistic influence of indium and cerium atoms in In₂S₃ nanocompounds for solar energy applications has been established by various experimental analyses complemented with theoretical investigations via DFT calculations.