A green approach to the fabrication of a TiO2/NiAl-LDH core-shell hybrid photocatalyst for efficient and selective solar-powered reduction of CO2 into value-added fuels

Exploring promising photocatalysts with high efficiency and selectivity for CO2 reduction holds paramount significance for resolving the energy crisis and various environmental problems associated with traditional fossil fuels. Here, we rationally design a core-shell hybrid photocatalyst in which anatase TiO2 hollow spheres serve as the core component and NiAl layered double hydroxide (LDH) nanoflakes serve as the shell component. The synthesis of the TiO2/LDH core-shell hybrid involves hydrothermal and calcination treatments without the use of environmentally toxic solvents or surfactants. Assorted experimental results demonstrate that the TiO2/LDH core-shell hybrid exhibits a strong light-harvesting ability, large surface area, porous structure, and extraordinary CO2 adsorption capability. In addition, the unique core-shell geometric structure of the TiO2/LDH hybrid results in a large interfacial contact area and thus provides a broader platform for efficient charge transfer. Benefiting from these structural and compositional features, the TiO2/LDH core-shell hybrid exhibits remarkable CO2 reduction activity, high selectivity (against water reduction), and more importantly, good stability during consecutive test cycles. Therefore, this work offers a promising approach to the rational design and fabrication of core-shell hybrid photocatalysts with potential applications in solar energy conversion and environmental protection.