Silver Induced In-Phase Electronic Interaction and Chloride Ion Repelling for Efficient Electrocatalytic Oxygen Evolution in Seawater Electrolysis

Abstract

Seawater electrolysis for hydrogen production has emerged as a focal point in hydrogen energy utilization technology due to its low carbon emissions and the abundance of seawater resources. However, the high chlorine content of seawater as an electrolyte negatively impacts the stability and performance of anodic catalysts. Herein, we design a silver integration strategy to repel surface Cl^– adsorption and modulate the electronic structure of the metal active center of NiCo bimetallic metal organic framework (MOF). The obtained Ag@NiCo MOF achieves an overpotential of 269 mV at a current density of 10 mA cm^–2 toward oxygen evolution reaction (OER) and maintains this performance over 500 h in simulated alkaline seawater without obvious degradation. The superior performance is because the in-phase electronic interaction induced by deposited Ag optimizes the electron state of MOF metal active sites. Moreover, deposited Ag in situ transforms into AgCl during OER further triggering the repulsion of Cl^– on the electrode surface. This not only facilitates the reaction kinetic but also helps repel chloride ions and enhances electrode stability and the selectivity for OER. The superior electrochemical performance and stability of Ag@NiCo MOF render them highly competitive among various catalysts for alkaline seawater spitting.