Microenvironment engineering of gas-involving energy electrocatalysis and device applications

Gas-involving electrochemical reactions, including gas-consuming reactions and gas-evolving reactions, play a critical role in the construction of clean energy conversion and storage devices. The reactions happen on the solid/liquid/gas three-phase interfaces, their reaction kinetics are greatly affected by the interfacial microenvironment. The microenvironment engineering has a significant impact on the intrinsic activity of the catalytically active site for electrocatalysts, which has received much attention. In this review, an overview of recent progresses in the design strategies of the microenvironment for electrocatalysts are provided with respect to the regulation of active sites, the enhancement of mass transfer process and the improvement of electronic conductivity. Notably, the correlations between the microenvironment engineering and electrocatalytic activities are discussed. The applications in the related devices such as water electrolyzer, fuel cells and metal-gas batteries are also presented. Finally, the existing challenges and research orientations of the microenvironment engineering for electrocatalysts and the related device applications are proposed.