Atomically Dispersed Interstitial Phosphorus Boosts Alkaline Hydrogen Evolution Performance of Co Catalysts

Abstract Introducing interstitial light atoms shows great potential in improving the intrinsic activity and stability of metal catalysts owing to strongly affecting the electronic structure and adsorption properties. However, filling atomically dispersed light atoms into metal lattices and further unveiling their interstitial effects are still limited by tightly arranged metal lattices. Herein, the study reports a calcination reduction assisted trace light atoms filling strategy to form a series of interstitial light single atoms filled Co‐based catalysts (Co‐X@NF, X = P, N and NF = nickel foam), therefore constructing monometallic atomic interfaces between P‐coordinated Co δ+ and Co 0 to promote alkaline hydrogen evolution reaction (HER). Noteworthy, the optimal Co‐P 0.43 @NF with rich monometallic atomic interfacial structure shows very high turnover frequency values (5.64 s −1 ), which is close to noble metal level and far exceeds non‐noble metal catalysts. Meanwhile, it maintains excellent stability of 150 h at 100 mA cm −2 . Theoretical studies prove that P‐coordinated Co δ+ promotes H 2 O dissociation and Co 0 optimizes H* adsorption energy, thus forming highly active monometallic atomic interfaces, which greatly accelerates the alkaline HER kinetics.