Another approach is based on TiO x NPs. Synthesized TiO x NPs were spin-coated onto a stainless steel mesh surface and subjected to a super-hydrophobic treatment of surface to test their performance as solar water evaporators. The test results showed that black TiO x efficiently produced water vapor with a solar thermal conversion efficiency as high as 50% under solar-simulated light irradiation with an intensity of 1000 W.m -2 (i.e., 1 Sun).