Wood–hydrogel composites coated with C3N4 photocatalyst for synchronous solar steam generation and photocatalytic degradation

Developing interfacial solar steam generation-based water desalination and purification systems is considered a viable solution to freshwater shortages and energy crises. The design and fabrication of thermal materials with broad solar absorption is critical for efficient utilization of full solar spectrum. Herein, a wood-based hydrogel evaporator coated with C 3 N 4 photocatalyst was explored for simultaneous solar evaporation and photocatalytic degradation. C 3 N 4 photocatalyst can absorb ultraviolet photons to generate electron–hole pairs for photocatalytic degradation. At the same time, PDA@ZIF-8 can capture near-infrared visible photons to produce heat, which further improves the photocatalytic efficiency. The optimized evaporator achieves a TC photocatalytic degradation of 96.70%. It also acquires a high solar evaporation rate of 2.64 kg m −2  h −1 with an energy conversion efficiency of 89.23% at 1.0 kW m −2 solar irradiation. This multifunctional wood-based hydrogel evaporator provides a feasible freshwater purification and waste treatment solution.