Electronic-Structure Tuning of Water-Splitting Nanocatalysts

The critical challenge of electrochemical water splitting (EWS) is to overcome the slow kinetics and large overpotential of the oxygen evolution reaction (OER). Although hydrogen evolution activity in acidic solutions has been achieved to a sufficient extent, acceptable activity of alkaline hydrogen evolution still remains to be achieved. Strategies such as alloying, doping, interfacing, oxygen-vacancy engineering, and edge-defect engineering can selectively adjust the electronic structure of nanocatalysts for enhanced EWS catalysis. To date, significant effort has been expended toward constructing efficient EWS electrocatalysts from two promising avenues: low-Pt precious metal (LPM) catalysts or non-precious metal (NPM) catalysts. Electrochemical water splitting (EWS) represents a promising pathway for the storage of intermittent energies, such as wind and solar, in the form of hydrogen gas. The operational efficiency of EWS is governed in part by the electrocatalysts for two electrode reactions, namely, the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In this review, we highlight recent fundamental and experimental progress on tuning the electronic structure of electrocatalysts for enhanced EWS. In particular, we discuss several strategies to adjust the electronic structure of nanoelectrocatalysts, including: alloying, doping, interfacing, incorporating oxygen vacancies, and edge-defect engineering. Finally, some invigorating perspectives for future research directions are also provided. Electrochemical water splitting (EWS) represents a promising pathway for the storage of intermittent energies, such as wind and solar, in the form of hydrogen gas. The operational efficiency of EWS is governed in part by the electrocatalysts for two electrode reactions, namely, the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In this review, we highlight recent fundamental and experimental progress on tuning the electronic structure of electrocatalysts for enhanced EWS. In particular, we discuss several strategies to adjust the electronic structure of nanoelectrocatalysts, including: alloying, doping, interfacing, incorporating oxygen vacancies, and edge-defect engineering. Finally, some invigorating perspectives for future research directions are also provided.