Alloyed Pt Single‐Atom Catalysts for Durable PEM Water Electrolyzer

The high cost of noble metals is one of the key factors hindering the large‐scale application of proton exchange membrane (PEM) water electrolyzer for hydrogen production. Recently, single‐atom catalysts (SACs) with a potential of maximum atom utilization efficiency enable lowering the metal amount as much as possible; unfortunately, their durability remains a challenge under PEM water electrolyzer working conditions. Herein, a highly‐stable alloyed Pt SAC is demonstrated through a plasma‐assisted alloying strategy and applies to a PEM water electrolyzer. In this catalyst, single Pt atoms are firmly anchored onto a Ru support via a robust metal–metal bonding strength, as evidenced by these complementary characterizations. This SAC is used in a PEM water electrolyzer system to achieve a cell voltage as low as 1.8 V at 1000 mA cm −2 . Impressively, it can operate over 1000 h without obvious decay, and the catalyst is present in the form of individual Pt atoms. To the knowledge, this will be the first SAC attempt at a cell level toward long‐term PEM. This work paves the way for designing durable SACs employed in the actual working condition in the PEM water electrolyzer.