Stackable nickel–cobalt@polydopamine nanosheet based photothermal sponges for highly efficient solar steam generation

Ni 1 Co 3 @PDA nanosheets were utilized as photothermal materials in a kerosene lamp-like evaporator for solar steam generation. A high evaporation rate of 2.42 kg m −2 h −1 with a corresponding energy efficiency beyond the theoretical limit was achieved.