Biomass Photothermal Hydrogel Based on Tea Leaves Residue for Cogeneration of Clean Water and Electricity

Abstract Interfacial solar‐driven evaporation has attracted much attention due to its high photothermal conversion efficiency. The core technology of photothermal conversion is photothermal materials, biomass photothermal materials are characterized by low cost, large specific surface area, environmental friendliness, and renewability. Discarded tea leaf residue (TLR) is harmful to the environment and has good recycling potential. In this work, a high‐performance, low‐cost, environmentally friendly solar steam generation material is fabricated by combining polyvinyl alcohol hydrogels and biomass photothermal material TLR. TheTLR hydrogel utilizes solar energy as a renewable energy source for desalination. Under 1.0 kW m⁻² simulated solar irradiation, the evaporation rate is 1.35 kg m⁻² h⁻¹ and the evaporation efficiency is 93.35%. The waste heat generated during solar water evaporation can be effectively used for synergistic water‐electricity cogeneration, thus achieving an evaporation rate and voltage of 0.91 kg m⁻² h⁻¹ and 58.8 mV under 1.0 kW m⁻² solar irradiation, respectively. The prepared hydrogel can also be used as a good organic dye adsorbent material, which has a broad application prospect in wastewater treatment. This method for preparing solar absorbers reduces manufacturing costs environmentally friendly and guides the potential practical application using discarded waste.