In-situ engineering of flower-like CdIn₂S₄/CaIn₂S₄ nanoarchitecture: A hybrid photocatalyst with improved charge dynamics and H₂ production

In the quest for sustainable energy solutions, semiconductor-based photocatalysis has emerged as a promising strategy for hydrogen (H₂) production via water splitting. Herein, we have fabricated a series of hierarchical CdIn₂S₄/CaIn₂S₄ heterostructures using in-situ hydrothermal techniques, ensuring well-defined heterojunction interfaces between CdIn₂S₄ and CaIn₂S₄. The prepared CdIn₂S₄/CaIn₂S₄ n-n heterostructure has a unique hierarchical 3D flower-like morphology with flexible porosity. The hierarchical morphology provided high surface area and porosity, thus exposing a larger quantity of active sites, while the heterojunction facilitated efficient electron-hole pair separation. The growth of CaIn₂S₄ over CdIn₂S₄ enables a strong interfacial contact, which facilitates efficient charge dynamics and improves light harvesting, resulting in excellent visible light-driven photocatalytic H₂ production performance. A comprehensive characterization of the hybrid materials revealed the physiochemical and optoelectronic features of the CdIn₂S₄/CaIn₂S₄ binary hybrid materials. The optimal CdIn₂S₄/CaIn₂S₄-30 (CC30) hybrid photocatalyst exhibited a superior PHE rate of 1759 µmolg⁻¹h⁻¹ with an apparent conversion efficiency of 1.93 %, which is 18.9 and 6.6 times higher than the CaIn₂S₄ and CdIn₂S₄ materials, respectively. The enhanced H₂ production efficiency of the heterostructure has been attributed to the synergistic effects of the hybrid structure, which promoted efficient light absorption, accelerated charge migration, and strong resistance to photoinduced charge recombination. This work highlights a new perspective on ternary metal chalcogenide engineering and establishes a promising platform for the rational design of efficient energy materials.