Gradient hydrophobic evaporator based on ODT modified Co3O4/NF enables efficient desalination and thermoelectric power generation

Abstract

The utilization of solar-driven interfacial evaporation technology for desalination and power generation is a promising strategy for dealing with the water and energy shortage crisis, but the balance between high photo-thermal conversion and minimizing heat loss is the major challenge that hinder its widespread application.. In this work, we innovatively design a surface-to-bottom gradient hydrophobic evaporator. Within array structured Co3O4 nanoparticles grown on nickel foam (Co3O4/NF), the trapping light system can realize superior photo-thermal conversion efficiency. Applying ortho-octadecanethiol (ODT) to the surface of Co3O4/NF to construct the gradient hydrophobic structure can optimize the water content within the inner pores, thereby minimizing heat loss. Under 1 sun illumination, the evaporation device realizes a prominent evaporation rate of 1.76 kg m-2h−1, which is 11.4 % higher than that of hydrophilic counterparts (1.55 kg m-2h−1). In addition, the gradient hydrophobic evaporator operates stably in 3.5 wt% NaCl for more than 8 h without salt crystallization. Furthermore, it achieves a sunlight-enhanced voltage of about 97.8 mV and an open-circuit current of 14.6 mA. Our research introduces an innovative solar-powered water treatment technology that effectively addresses the dual challenges of desalination and electricity generation, paving the way for sustainable development.