Superhydrophilic Nickel Nanoparticles with Core–Shell Structure To Decorate Copper Mesh for Efficient Oil/Water Separation

Recently, oil/water separation has attracted intensive attention due to the frequent crude oil spill accidents and the increasing amount of industrial wastewater. Thousands of outstanding achievements have been reported on the basis of membranes with superhydrophilicity and underwater superoleophobicity. However, a universal approach combining cheaper reagents with easier operations to fabricate superhydrophilic materials for effective oil/water separation is still a challenge and greatly encouraged. In the present work, we fabricate the superhydrophilic copper mesh decorated with nickel nanoparticles (Ni-NPs) via electrodeposition in fluorine-containing electrolyte. The size of Ni-NPs that consists of a metal Ni core and a polar NiO/Ni(OH)2 shell is about 300 nm; what's more, the Ni-NPs combine with each other to form treelike nickel crystals by varying the experimental parameters. This optimized mesh exhibits remarkable oil/water separation performance. The oil content in separated water is lower than 3 ppm, and the stability in acidic, alkaline, and salt solutions and the properties for repeated use are also excellent. Further, we provide a novel approach to synthesis superhydrophilic nanoparticles with a core–shell structure for coating or other applications such as catalysis, self-cleaning, antifogging, and so on.