Cooperative Cobalt-Doped and Carboxylate Anions Modification of NiFe-Layered Double Hydroxides for Improving Oxygen...

The disparity of the fast electron-slow proton process significantly hinders the catalytic efficiency of the oxygen evolution reaction (OER) in water splitting, so it is necessary to develop efficient and stable catalytic materials to mitigate elevated overpotentials. In this study, a one-step hydrothermal approach was utilized to synthesize a cobalt-doped, carboxylic-acid-modified NiFe-layered double hydroxide (CoNiFe-LDH/NF) catalyst with significantly enhanced intrinsic catalytic activity. Introducing Co promotes the generation of active components, and carboxylate anions accelerate proton transfer, the synergistic interaction of which endows CoNiFe-LDH/NF with superior OER performance. Experimental results show that the catalyst has an overpotential as low as 230 mV at 100 mA cm^-2, a Tafel slope as low as 38.5 mV dec^-1, and excellent stability for 120 h at a current density of 10 mA cm^-2. Furthermore, mechanistic exploration by molecular probe detection and the pH-dependent experiment showed that the modified CoNiFe-LDH/NF was closer to the lattice oxygen oxidation mechanism (LOM). This study provides an effective strategy to improve the performance of layered OER catalytic materials.