Integrative solar absorbers for highly efficient solar steam generation

Abstract

Herein, carbonized melamine foams obtained through one-step calcination were first used as integrative solar absorbers (ISAs) for water evaporation, realizing highly efficient solar steam generation. The optimized ISA shows excellent light absorption (>96%) for solar energy due to the features of high porosity, lightweight, mechanical robustness inherited from melamine foams, as well as low thermal conductivities attributed to the appropriate pore scale and high nitrogen content, beneficial for the decrease of thermal diffusions. As a result, compared with the former reports, the optimized ISA reported herein exhibits one of the best performances for solar steam generation with a water evaporation rate of 1.270 kg m⁻² h⁻¹ and an energy conversion efficiency of 87.3% under 1 kW m⁻² solar illumination and realizes effective solar desalinations. In addition, the ISAs can work out efficient water evaporation under a high humidity of 90%. Due to their simple preparation, recyclability, and aforementioned extraordinary performance, the ISAs can be expected to be potential solar absorbers for commercial, renewable, and portable solar steam generations.