Confinement Effects in Individual Carbon Encapsulated Nonprecious Metal‐Based Electrocatalysts

The evolution of cost‐effective and reserve‐rich nonprecious metals (NPMs) to replace precious metal electrocatalysts is of significant interest in modern electrocatalysis. The confinement effects in NPM‐based nanoparticles encapsulated in carbon nanoshells have been considered as an emerging and efficient way to special types of electrocatalysts which facilitate electrocatalytic activity and stability, even under rigorous conditions. This review focuses on the unique individual carbon encapsulation for high‐performance design of NPM‐based electrocatalysts, outlining all confinement synthesis methods, mechanistic studies on confinement effects, and the emerging practical reactions. It begins first introducing the synthetic methods for NPM‐based core@carbon shell electrocatalysts, and then follows clarification of the relationship between the fundamental confinement effects and the performance improvement of carbon shell encapsulating NPM‐based electrocatalysts. Further and detailed discussions on the alloying effect, doping effect, and heterojunction effect of the NPM‐based core to alter the electronic situation which affects the electrocatalytic performance are subsequently provided. Finally, the review provides a perspective on challenges and opportunities in future research with respect to both in‐depth theoretical research and potential design concept of such NPM‐based core@carbon shell electrocatalysts.