Dual Engineering of Electronic Structure and Lattice Strain via Ce Doping in NiMn‐LDH for Oxygen Evolution Reaction

Water electrolysis is a more sustainable way to produce green hydrogen than steam methanol reforming or coal gasification. Its efficiency is limited by slow oxygen evolution processes at the anode. Highly effective anodic electrocatalysts are difficult to produce. Layered double hydroxide is a promising and thoroughly researched OER material, however, long-term stability issues arise. In this study, we examine the modification of the electronic structure of NiMn LDH through the introduction of Ce doping. The analysis of the material using XPS and XRD indicates that Ce is effectively integrated into the NiMn crystal structure, resulting in lattice distortion and alterations to the electronic structure when doped at concentrations of up to 5%. Furthermore, various electrochemical characterizations indicated that Ce doping increased the number of electrochemically active sites, improved electronic conductivity, and optimized the electrochemical kinetics. The 5% Ce-doped NiMn LDH demonstrated a current density of 30 mA/cm2 at an overpotential of 561 mV, which is significantly lower than the 638 mV overpotential observed for NiMn LDH and considerably superior to that of commercial RuO2. The system exhibited complete stability throughout a 15-h operational duration at a consistent applied current density of 15 mA/cm2, with no indications of degradation observed.