The Synergistic Activation of Ce‐Doping and CoP/Ni3P Hybrid Interaction for Efficient Water Splitting at Large‐Current‐Density

Abstract The high intermediate (H*, OH*) energy barriers and slow mass/charge transfer increase the overpotential of alkaline water electrolysis at large‐current‐density. Engineering the electronic structure with the morphology of the catalyst to reduce energy barriers and improve mass/charge transportation is effective but remains challenging. Herein, a Ce‐doped CoP nanosheet is hybrid with Ni 3 P@NF (Ni foam) support to enhance mass/charge transfer, tune energy barriers, and improve water‐splitting kinetics through a synergistic activation. The engineered Ce 0.2 ‐CoP/Ni 3 P@NF cathode exhibits an ultralow overpotential (η 500 , η 1000 ) of −185, and −225 mV at −500 and −1000 mA cm −2 in 1.0 m KOH, along with an excellent pH‐universality. Impressively, an electrolyzer using the Ce 0.2 ‐CoP/Ni 3 P@NF cathode can afford 500 mA cm −2 at a cell voltage of only 1.775 V and maintain stable electrolysis for 200 h in 25 wt% KOH (50 °C). Characterization and density functional theory calculation further reveal the Ce‐doping and CoP/Ni 3 P hybrid interaction synergistically downshift d‐band centers (ε d = −2.0 eV) of Ce 0.2 ‐CoP/Ni 3 P to the Fermi level, thereby activate local electronic structure for accelerating H 2 O dissociation and optimizing Gibbs free energy of hydrogen adsorption (∆ G H* ).