Highly efficient solar water evaporation by wood through one-step in-situ synthesis of carbon dots

Abstract

Solar evaporation provides an effective solution to solve the scarcity of freshwater resources. Biomass-based solar evaporators have attracted significant interest, because of their environmental safety. However, due to the high latent heat of evaporation for water, most biomass-based solar evaporators exhibit low water vapor generation rates. In this work, we have developed a wood-based solar evaporator (CDs-Wood) by just one step in-situ synthesis of carbon dots (CDs) using the lignin in wood as the carbon source, and the latent heat of evaporation for water in CDs-Wood has significantly decreased from 2257.5 J g−1 to 1003.8 J g−1, which has resulted in a water vapor generation rate as high as 2.86 kg m−2h−1. CDs-Wood exhibits extensive optical absorption capacity (95.3 %), high solar steam conversion efficiency (80 %), significant adaptability to low-temperature conditions, and excellent salt resistance. This work provides an efficient and potentially scalable solution for designing all-biomass-based solar steam evaporators.