Underwater superoleophobic TiO₂/porous metal matrix with self-cleaning properties for high performance oil/water separation

Porous metal materials with special surface wettability are widely used in oily wastewater treatment. To realize efficient oil/water separation of porous metal material, layered spherical TiO₂ and “woodchip” NiO micro-nano structures were constructed on the surface of nickel foam (NF) matrix by hydrothermal method, which endowed the porous metal material with superhydrophilic and underwater superoleophobic (SHI/USOB) characteristics. Moreover, the separation efficiency of various oil/water mixtures remained above 98%, and the water flux exceeded 2.66 × 10⁵ L m⁻² h⁻¹. Meanwhile, the uniformly supported TiO₂ nanoparticles showed excellent self-cleaning performance, and the oil droplets remaining on the sample surface could be effectively degraded under ultraviolet irradiation for 8 h. TiO₂/NF has a lot of potential because of its three-dimensional micro-nano porous structure, self-cleaning capabilities and environmental friendliness.