A salt-free superhydrophilic metal-organic framework photothermal textile for portable and efficient solar evaporator

Solar-driven interface steam generation is rapidly emerging as a water purification technology. However, an efficient and facile method to fabricate high-performance and flexible solar evaporators and simultaneously prevent salt accumulation for portable applications is still a challenge. Herein, a super-hydrophilic, conformal and robust Cu-based metal-organic framework (Cu-MOF) absorber coating is strongly immobilized on the commercial textile surface by using sputtered Cu film as a bonding layer, which ensures strong adhesion between the textile substrate and Cu-MOF coating. Benefiting from the excellent capillary effect and powerful water pumping capability, no salt accumulation was observed on the upper surface of Cu-MOF photothermal textile (CMPT) even at a salinity of 9.5 wt% for over 12 h during evaporation. Together with superior light absorptance (95.9%), originating from unique light trapping hierarchical structure of Cu-MOF, and superb air permeability, the CMPT achieved a high evaporation rate of 1.52 kg/m2 h under one sun irradiation and simultaneous salt rejection during vapors generation. Moreover, owing to the outstanding structural design, the CMPT possesses high flexibility, superior mechanical strength and excellent chemical stability under harsh environments. The current study presents a simple and straightforward approach for surface-immobilized MOF-coating on textile fibers for practical applications in portable solar steam generators.