Recent Development of Ni/Fe-Based Micro/Nanostructures toward Photo/Electrochemical Water Oxidation

The oxygen evolution reaction (OER), as an important process involved in water splitting and rechargeable metal-air batteries, has drawn increasing attention in the context of clean energy generation and efficient energy storage. This review concerns the progress and new discoveries in the field of Ni/Fe-based micro/nanostructures toward electrochemical and photo-electrochemical (PEC) water oxidation during last few years. First, toward the design and construction of new electrocatalysis, different types of current Ni/Fe-based compounds for OER are summarized. The mechanism studies of the active phases and positions of Ni/Fe-based micro/nanostructures are further introduced to understand the properties of catalytic active sites, which could facilitate further improving the performance of Ni/Fe-based OER electrocatalysts. Second, splitting water using sunlight with low overpotential is another important target in making solar-to-hydrogen micro/nanodevices, and thus attention is then focused on the development of several important Ni/Fe-based PEC catalysts. Third, the recent theoretical calculations on the OER mechanism during water splitting and insights into electronic structures are analyzed; finally, the future trends and perspectives are also discussed briefly.