Operando-reconstructed polyatomic ion layers boost the activity and stability of industrial current–density water splitting

原位重构的多原子离子层打破活性-稳定平衡提升大电流下工业电解水

Metal–organic frameworks have garnered attention as highly efficient pre-electrocatalysts for the oxygen evolution reaction(OER).Current structure–activity relationships primarily rely on the assumption that the complete dissolution of organic ligands occurs during electrocatalysis.Herein,modeling based on NiFe Prussian blue analogs(NiFe-PBAs)show that cyanide ligands leach from the matrix and subsequently oxidize to corresponding inorganic ions(ammonium and carbonate)that re-adsorb onto the surface of NiFe OOH during the OER process.Interestingly,the surface-adsorbed inorganic ions induce the OER reaction of NiFe OOH to switch from the adsorbate evolution to the lattice-oxygen–mediated mechanism,thus contributing to the high activity.In addition,this reconstructed inorganic ion layer acting as a versatile protective layer can prevent the dissolution of metal sites to maintain contact between catalytic sites and reactive ions,thus breaking the activity–stability trade-off.Consequently,our constructed NiFePBAs exhibit excellent durability for 1250 h with an ultralow overpotential of 253 mV at 100 mA cm2.The scale-up NiFe-PBAs operated with a low energy consumption of4.18 kWh m3 H2 in industrial water electrolysis equipment.The economic analysis of the entire life cycle demonstrates that this green hydrogen production is priced at US$2.59 kg^(-1)H_(2),meeting global targets(<US$2.5 kg^(-1)H_(2)).