Electron Shuttling of Iron‐Oxygen‐Cobalt Bridging in Cobalt Assembled Iron Oxyhydroxide Catalyst Boosts the Urea Oxidation Stability and Activity

Abstract Iron (Fe)‐based materials hold great potential as urea oxidation reaction (UOR) catalysts, however, the deactivation of active Fe‐oxyhydroxide (FeOOH) species induced by its dissolution during catalytic process under high current densities is still significant challenge. Herein, cobalt (Co) assembled FeOOH is constructed, and the formation of Iron‐Oxygen‐Cobalt (Fe‐O‐Co) bridging triggers the electron transfer from Co to Fe sites. This electron shuttling induces the low valence state of Fe active sites in FeOOH. This Co‐FeOOH catalyst achieves a current density of 1000 mA cm ⁻² at a low voltage of merely 1.59 V, showing a substantial improvement compared to pure FeOOH (1.97 V). Meanwhile, in the urea‐assisted anion exchange membrane electrolyzer, after 24 h continuous operation at a current density of 1000 mA cm ⁻² , the voltage fluctuation of Co‐FeOOH is merely 12.4%, significantly lower than that of FeOOH (49.9%). The in situ experiments and theoretical calculations demonstrate the electron transfer from Co to Fe sites in Fe‐O‐Co bridging endows the suppressive Fe‐segregation, fast charge transfer of active Fe(Co)OOH phase and negative‐shifted d‐band center of metal active sites, boosting its UOR stability and activity.