High-Performance Water Purification and Synergistic Hydrovoltaic by Avocado Peels Decorated With Carbon Dots

Interfacial solar evaporation technology is emerging as a promising solution to the freshwater shortage problem. However, the complex manufacturing process and high cost of artificial photothermal materials hinder its widespread application. This work presents a novel solar evaporator (HCAP), distinct from multi-step methods and carbonized photothermal structures, developed by decorating avocado peels with carbon dots using a one-step hydrothermal method. The carbonized avocado peel retains the intrinsic porous microstructure, providing excellent channels for water evaporation. Under one solar irradiation, the average evaporation rate of HCAP was 2.79 ± 0.03 kg m^-2 h^-1, the water evaporation efficiency was 155.8%, and the photothermal conversion efficiency was 86%. Compared to the control group of bulk water system, the evaporation rate of HCAP increased by approximately fivefold. Furthermore, owing to its numerous orderly channels and micropores, HCAP evaporators can accelerate the transport of ions and generate excellent hydrovoltaic power, with the output performance of 110.2 mV and 10.54 μA, under one-sun irradiation. During evaporation, salt concentration gradient and light intensity were investigated as key factors affecting high electricity generation. This work provides a simple and sustainable way to use biomass materials for seawater desalination, wastewater purification, and hydrovoltaic production, driven by solar energy.