Trace rare earth modulated tetranickel nitride embedded in mesoporous carbon as electrocatalysts for the oxygen evolution reaction

The sluggish kinetics of anodic oxygen evolution reaction (OER) has been the restricted factor for large-scale hydrogen production from water electrolysis. Exploring highly efficient OER electrocatalysts is essential to varied renewable energy storage and conversion devices. In this work, we designed and fabricated subminiature tetranickel nitride (Ni4N) nanocrystallines modulated by trace amounts of rare earth (RE) encapsulated in ultrathin mesoporous nitrogen-doped carbon shells (RE-Ni4N@mesoNC) derived from ultrathin layered hydroxide nanosheets as highly active and stable electrocatalysts for the OER in water spilling. In view of the advantages of excellent electrical conductivity, adjustable surface electronic structure and a high density of utilizable active sites, the as-synthesized RE-Ni4N@mesoNC electrodes exhibit more superior performance than RE-free Ni4N@mesoNC and commercial IrO2. The optimal La–Ni4N@mesoNC achieved a lower overpotential of 330 mV at the current density of 10 mA cm−2 and a smaller Tafel slope of 66 mV·dec−1. And the La–Ni4N@mesoNC electrode also exhibit the excellent stability of continuous 72 h i-t tests and the overlapped polarization curve before and after 3000 consecutive CV cycles.