Reconstructed Hydroxyl Coordination Field Enhances Mass Transfer for Efficient Electrocatalytic Water Oxidation

Abstract

Mass transfer factor plays an indispensable role in high current density to accelerate the oxygen evolution reaction (OER) process, yet research on modulating reactant mass transport remains limited. Herein, by leveraging the dual acid-base properties of aluminum sites, both the activation of the electronic activity of the layer for layered double hydroxides (LDH) and construction of the interlayer hydroxide coordination field (IHCF) have been achieved through in situ electrochemical reconstruction. It not only facilitates charge transfer and the surface catalytic transformation of reaction intermediates but, most notably, the presence of the IHCF significantly enhances the mass transport of reactants. As a result, the overpotential of LDHs with IHCF is only 164 mV, significantly better than the reported Ni-based catalysts. Deuterium kinetic isotope effect experiments and pH-dependence measurements demonstrate that the IHCF effectively enhances substrate mass transport capability and structural stability, thereby accelerating the proton-coupled electron transfer process. To further validate the high mass transport characteristics, stability tests of the alkaline flow electrolyzer show that catalysts maintain over 1000 h of stability at a high current density. This work suggests that the IHCF effect can be utilized for further design and synthesis of efficient water oxidation catalysts for practical application.