3D bionic flower-like structure water-storage microcapsule evaporator for efficient solar interfacial evaporation

Abstract

Solar desalination technology is the cleanest and lowest energy-consuming way to produce fresh water. Nevertheless, the low vapor generation rate of unmodified evaporation membranes limits their practical applications. Herein, an evaporator with three-dimensional water-storage microcapsules and a tungsten nitride (WN) bionic flower-like structure composite (WN@NC) was prepared by combining tungsten nitride (WN) nanoparticles with carbon. WN has high light absorption efficiency, while the porous channels inside the NC enable incident light to be reflected and absorbed multiple times within. Benefiting from the synergistic effect between the porous channels of flower-like NC and the light absorption capacity of WN, WN@NC achieves a high light absorption efficiency of 98.7% in the infrared light region, the main heat-generating band. As a result, the evaporator achieves a vapor generation rate of 1.82 kg m⁻² h⁻¹ and an energy utilization efficiency of 96.5%. The continuous evaporation test lasting for 7 days still maintains an average daily vapor generation rate of 8.2 kg m⁻². This study provides a new strategy for further improving the vapor generation rate of solar interfacial evaporators.