Hierarchically porous nickel foam supported Co-NCNT arrays for efficient solar water evaporation, wastewater purification and electricity generation

Abstract

Developing advanced solar-powered interfacial evaporators with three-dimensional porous configuration integrating key components of effective solar conversion, adequate water transmission, and flexible thermal modulation is highly demanded but remains a major challenge for solar steam generation. In this work, nitrogen-doped carbon nanotube@Co arrays are in situ grown on three-dimensional macroporous nickel foam (Co-NCNT/NF) to act as a hierarchically porous configuration for solar water evaporation. Synergistic cooperation between Co nanoparticles and NCNT leads to outstanding broadband absorption across whole solar spectrum. Under 1 sun irradiation, the Co-NCNT/NF can rapidly respond to solar light and generate a stable surface temperature as high as 41.5 °C during solar evaporation process. Benefiting from the multifunctional structure features, the Co-NCNT/NF achieves a high evaporation rate of 1.65 kg m−2 h−1 and an evaporation efficiency up to 97.5 % under 1 sun irradiation. Such performance facilitates the continuous production of clean water from seawater and the effective purification of various wastewater. Moreover, comprehensive utilization of additional heat loss during solar water evaporation for thermoelectric power generation is demonstrated as well.