Ce-doped NiOOH coupled with Ni nanocrystals endowing high-current-density water oxidation on iron-free catalysts

Developing iron-free transition-metal based catalysts to overcome ion-leaching degradation is still a critical challenge due to their inherent low activity and poor electron transfer characteristics for oxygen evolution reaction (OER). Herein, an iron-free catalytic material integrating amorphous Ce-doped NiOOH with Ni nanocrystals was synthesized via a one-step electrodeposition method, achieving scalable fabrication of a uniform anode over 600 cm 2 . It shows remarkably low overpotentials of 190 mV and 332 mV to achieve 10 and 1000 mA cm −2 in 1 M KOH, respectively. Moreover, it maintains 98.7 % activity retention after 1000 h of continuous operation at 1000 mA cm −2 . XPS, XANES, in-situ Raman spectroscopy and density functional theory (DFT) calculations demonstrate that Ni nanocrystals significantly enhance the interfacial and bulk charge transport in NiOOH, while Ce doping substantially promotes both the pre-oxidation process and OER kinetics. This work provides insights for designing iron-free catalytic materials with high alkaline OER performance.