High‐Performance Solar‐Thermal Hydrogel Based on Waste Biomass Materials for Power Generation and Water Purification

Global energy crisis, freshwater shortage, and other problems make the development and utilization of green energy particularly urgent. As an efficient solar‐thermal technology, solar interface evaporation has demonstrated great application potential in fields such as water purification and steam power generation. The browning of the waste biomass materials (WBM) result in the production of eumelanin or melanoidin, which adheres to the fibrous surface structure of the peel and promotes light absorption. The utilization of WBM as biomass solar‐thermal materials is characterized by low cost, environmental friendliness, and renewability. In this work, an environmentally friendly and highly efficient solar evaporator was constructed using WBM and polyvinyl alcohol carrier. When exposed to 1.0 kW m −2 simulated sunlight illumination, the system achieves an outstanding evaporation rate of 1.48 kg m −2 h −1 , corresponding to an energy conversion efficiency of 82.49%. By utilizing waste heat from the solar‐driven evaporation process, the system enables concurrent water–electricity cogeneration, yielding a consistent voltage output of 137 mV under 5.0 kW m −2 solar illumination. Additionally, the hydrogel can serve as highly effective organic dye adsorbents, showcasing significant promise for wastewater treatment applications. This approach to fabricating solar absorbers not only reduces production costs but also enhances potential practical utility by repurposing discarded materials.