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

Mn+1AXn (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 V2(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 V2(Sn, A)C are highly flexible to react with electrolyte. As a result, the V2(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 V2SnC. 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. Alkaline water electrolysis allows the use of non‐precious metal (e.g., Ni, Co, Fe‐based) oxygen evolution reaction (OER) catalysts. Herein, a new family of nanolaminated MAX phases, V2(Sn, A)C (A = Ni, Co, Fe) is reported, which can serve as a highly efficient OER electro‐catalysts after undergoing self‐reconstruction in alkaline media, affording a superior catalytic activity and long‐term stability.