I Single‐Atom Doped P‐Rich CoP _n Nanocluster@CoP with Enhanced HER

Abstract Constructing I single‐atom (I _SA ) doped CoP electrocatalyst for HER is extremely challenging and has not been reported to date. Herein, an I _SA doping‐phosphatization strategy is proposed to prepare a novel I single‐atom doped P‐rich CoP _n nanocluster@CoP electrocatalyst (I _SA ‐CoP _n /CoP) with enhanced HER performance first. I _SA ‐CoP _n /CoP shows a low overpotential of only 44 and 81 mV in 0.5 m H ₂ SO ₄ solution, to drive a current density of 10 and 100 mA cm ⁻² . I _SA and P‐rich CoP _n nanocluster show unique synergies, which can optimize the H adsorption energy and accelerate the kinetics of HER in the CoP system. The intermediate I─H bond vibration peak is directly observed through in situ Raman testing, demonstrating that I _SA doping helps accelerate the HER process. Additionally, the ΔG _H of I _SA ‐CoP _n /CoP is only 0.05 eV by density functional theory (DFT) calculation, which is conducive to H ₂ evolution.