Self‐Reconstruction of Single‐Atom‐Thick A Layers in Nanolaminated MAX Phases for Enhanced Oxygen Evolution

Abstract M n+1 AX n (MAX) phases are a family of nanolaminated ternary carbide/nitride, which are generally investigated as high‐safety structural materials, but their direct applications on electrocatalysis is still far from reality. Here, it is shown that by taking the advantages of self‐reconstruction, a unique class of MAX phases of V 2 (Sn, A)C (A = Ni, Co, Fe) can be adopted as efficient catalysts for oxygen evolution reaction (OER). The specific single‐atomic‐thick (Sn, A) layers within V–C networks in V 2 (Sn, A)C are highly flexible to react with electrolyte. As a result, the V 2 (Sn, Ni)C (VSNC) can maintain bulk crystalline structure, and merely encounter surface reconstruction to generate Ni‐based oxyhydroxide accompanying with the self‐doping of V and Sn elements under alkaline OER condition. The surface‐reconstructed VSNC exhibits significantly enhanced OER performance to that of reconstructed Ni nanopowder and V 2 SnC. Density functional theory simulations indicate that the doping of Sn/V into γ‐NiOOH leads to the change of reaction pathway of alkaline OER, while the introduction of V can reduce the reaction barrier to facilitate the OER process. This study exhibits a new functionality of a unique MAX phase toward OER, which puts forward the potential applications of MAX phase materials in electrocatalysis and beyond.