Closed Pore Structured NiCo2O4-Coated Nickel Foams for Stable and Effective Oil/Water Separation

5 years ago

Closed Pore Structured NiCo2O4-Coated Nickel Foams for Stable and Effective Oil/Water Separation

Zhanheng Yan, Jianmin Ma, Lei Jiang, Xiaofang Zhang, Dongliang Tian, Xi Zheng, Yan Li

To solve the serious problem caused by oily wastewater pollution, unique interface designs, for example, membranes with superwetting properties such as superhydrophobicity/superoleophilicity and superhydrophilicity/underwater superoleophobicity, provide a good way to achieve oil/water separation. Here, inspired by the liquid storage property of the honeycomb structure, we propose a strategy to fabricate NiCo₂O₄-coated nickel foams for stable and efficient oil/water separation. NiCo₂O₄ with a closed-pore structure was formed by assembling nanoflakes with a micro/nanoscale hierarchical structure. Compared with nickel foam coated by NiCo₂O₄ with an open-pore structure (NiCo₂O₄ nanowires), the enclosed nanostructure of NiCo₂O₄ nanoflakes can firmly hold water for a more stable superhydrophilic/underwater superoleophobic interface. As a consequence, the NiCo₂O₄-nanoflake-coated nickel foam has a larger oil breakthrough pressure than the NiCo₂O₄-nanowire-coated nickel foam because of a slightly larger oil advancing angle and a lower underwater oil adhesion force, which makes it more stable and efficient for oil/water separation. Moreover, the NiCo₂O₄-coated nickel foams have excellent chemical and mechanical stability, and they are reusable for oil–water separation. This work will be beneficial for the design and development of stable underwater superoleophobic self-cleaning materials and related device applications, such as oil/water separation.

Publisher URL: http://dx.doi.org/10.1021/acsami.7b05385

DOI: 10.1021/acsami.7b05385