Electronic Modulation of the 3D Architectured Ni/Fe Oxyhydroxide Anchored N-Doped Carbon Aerogel with Much Improved OER Activity

It remains a big challenge to develop non-precious metal catalysts for oxygen evolution reaction (OER) in energy storage and conversion systems. Herein, a facile and cost-effective strategy is employed to in situ prepare the Ni/Fe oxyhydroxide anchored on nitrogen-doped carbon aerogel (NiFeO_x(OH)_y@NCA) for OER electrocatalysis. The as-prepared electrocatalyst displays a typical aerogel porous structure composed of interconnected nanoparticles with a large BET specific surface area of 231.16 m²·g⁻¹. In addition, the resulting NiFeO_x(OH)_y@NCA exhibits excellent OER performance with a low overpotential of 304 mV at 10 mA·cm⁻², a small Tafel slope of 72 mV·dec⁻¹, and excellent stability after 2000 CV cycles, which is superior to the commercial RuO₂ catalyst. The much enhanced OER performance is mainly derived from the abundant active sites, the high electrical conductivity of the Ni/Fe oxyhydroxide, and the efficient electronic transfer of the NCA structure. Density functional theory (DFT) calculations reveal that the introduction of the NCA regulates the surface electronic structure of Ni/Fe oxyhydroxide and increases the binding energy of intermediates as indicated by the d-band center theory. This work provides a new method for the construction of advanced aerogel-based materials for energy conversion and storage.