Integrated Coupling Utilization of the Solar Full Spectrum for Promoting Water Splitting Activity over a CIZS Semiconductor

Most of the existing photocatalysts can only use ultraviolet light and part of visible light, so broadening the spectrum response range and realizing the full spectrum coverage are key measures to improve the solar-to-hydrogen (STH) efficiency of photocatalytic water splitting. A spatially separated photothermal coupled photocatalytic (PTC) reaction system was designed using carbonized melamine foam (C-MF) as a substrate to absorb visible and infrared light and Cu0.04In0.25ZnSy@Ru (CIZS@Ru) as a photocatalyst to absorb UV–visible light (UV–vis). By comparing the three modes of bottom, liquid level, and self-floating, it is found that the surface temperature of the system has a significant effect on the hydrogen evolution activity. The monochromatic light and activation energy experiments verify that the enhancement of photocatalytic activity comes from the strengthened photothermal effect of the substrate. Combined with theoretical calculations, it is further confirmed that the introduction of photothermal materials provides additional kinetic energy for carrier transmission and promotes directional carrier transmission efficiency. Based on the photoenergy–thermal integrated catalytic strategy, the hydrogen production rate reaches 603 mmol h–1 m–2. The structural design of photocatalysis has potential application in the field of photoenergy–fuel conversion.