Implanting Atomically Dispersed Fe and Mo Sites into 3D Scaffolds: A Scalable Route to Bifunctional Water Splitting Electrocatalysts

ABSTRACT Due to geometric constraints of planar substrates and poor electrical interface properties, overcoming the performance bottlenecks of single‐atom catalysts (SACs) in industrial water splitting remains a challenge. Here, we extend ion implantation technology to hierarchical three‐dimensional (3D) structures by constructing iron‐ and molybdenum‐based SACs uniformly anchored on carbon nanotube/nickel foam (CNT/NF) scaffolds. This physical approach enables the precise and scalable incorporation of metal atoms with high dispersion and accessibility on a scale of up to 8 inches. Implantation‐induced M─C coordination optimizes the electronic structure of active sites, lowering the reaction energy barrier by shifting the d‐band center and enhancing d‐p orbital hybridization. Concurrently, the 3D CNT/NF scaffold facilitates rapid charge transfer and efficient bubble release. An anion exchange membrane (AEM) electrolyzer with the two catalysts delivered a current density of 500 mA cm −2 at 1.66 V and 60°C and demonstrated robust durability over 100 h of continuous operation. This work establishes a scalable, effective platform for designing high‐performance, durable non‐precious SACs for practical water electrolysis.