Fabrication of Cu2NiSnS4 Nanoparticles on CdS with a Computationally Predicted Low Lattice Mismatch for Photoelectrochemical Hydrogen Evolution

The quaternary chalcogenide Cu2NiSnS4 (CNTS) nanoparticles, made up of earth-abundant elements, are one of the most favorable in the family of CM x TS (M x = Ni, Co, Cd, Fe, Mg, Mn, and Zn) for photoelectrochemical (PEC) hydrogen production due to the lowest resistivity, high absorption coefficient, and tunable band gap for sunlight absorption with suitable band edges. A p-type semiconductor, CNTS, is one of the stable photocathodes in the category of efficient ones. In this theoretical-aided experimental work, we illustrate the photoelectrochemical credibility of CNTS nanomaterials synthesized by a facile hot-injection method with CdS as a photoanode for hydrogen evolution with the interface of an alkaline electrolyte. Using density functional theory simulations, charge density difference, work function, and structural properties were evaluated, suggesting better lattice matching at the CNTS/CdS supercell interface with a lattice mismatch less than 3% along with better charge transfer. An optical band gap of 1.40 eV and a crystallite size of 48 nm were observed for CNTS evaluated. A high short-circuit current density of 6.656 mA cm-2 IPCE for the CNTS/CdS heterojunction was observed to be 14.87% at 505 nm. This promotes the heterojunction to possess minimal chances of material's phase change and hence stability.