operations. [3] Therefore, it is attractive and economical especially for small sized water plants and can be made into point-of-use potable water production apparatus. [1] Thanks to the interfacial heating idea and the fast development in rationally designed photothermal materials, the solar-driven water evaporation efficiency has been significantly improved in the last five years. [4] Various black materials with strong light absorbance in the solar spectrum range are intensively investigated, including carbon based materials, [4e,5] metal nanoparticles, [4c,6] conjugated polymers, [7] MXene, [8] and black metal oxides. [9] While, in theory, less than 1 mg cm −2 of these materials would efficiently absorb the majority of the sunlight, in reality it is prohibitively difficult to fabricate a singlephase photothermal membrane with such a small amount of material that nevertheless possesses satisfactory operation stability and mechanical strength for practical uses. Therefore, composite, instead of single-phase, photothermal membrane is typically fabricated where an additional phase is used as a support to increase the structural stability, with the most popular configuration being a separate thin active photothermal material layer on top of an inactive and generally porous supporting substrate, such as paper, [6a] wood, [5j,7b,10] metal mesh, [7a,9c] macroporous silica, [5l] cellulose, [5i,9a,b] AAO membrane, [6c] expanded polystyrene (EPS), [5d,f,h] etc. Generally, the top photothermal layer is rationally designed and made into highly porous structure in literatures (1) to increase its light absorbance by creating multiple reflections inside the pores, [11] (2) to provide passageways for efficient water supply, and (3) to increase the material/water interface for fast heat transfer, all of which are conducive to highly efficient solar distillation. However, the evil side of the highly porous structure as well as the ultrathin thickness of the top light absorbent layer brings about inevitable problems in real applications, such as fragileness, weak wear and abrasion resistance, and difficulty in removal of foulants and contaminants.It has to be noticed that, in solar distillation, the optical and thermal properties of photothermal materials are overwhelmingly investigated and optimized at their dry state, while their solar distillation performances are in fact measured when theyThe design and fabrication of efficient photothermal materials is the key issue in solar-driven water evaporation. In this work, a robust CuCr 2 O 4 /SiO 2 composite membrane with outstanding solar-driven water evaporation performance (1.32 kg m −2 h −1 ) under one sun irradiation is rationally designed and synthesized by using quartz glass fibrous membrane as supporting matrix and stable CuCr 2 O 4 particles as the active light absorber. Instead of coating a separate layer on top of the support, the CuCr 2 O 4 particles are evenly distributed inside the matrix, which endows the membrane with great mechanical strength and exc...
