Single-Walled Carbon Nanotubes Wrapped CoFe₂O₄ Nanorods with Enriched Oxygen Vacancies for Efficient Overall Water Splitting

The development of highly active and stable non-noble-metal electrocatalysts for water splitting is the main title toward energy conversion systems. CoFe2O4 has been reported as a promising oxygen evolution reaction (OER) electrocatalyst. However, CoFe2O4 showed poor conductivity and sluggish electrocatalysis in the hydrogen evolution reaction (HER). In this work a new hybrid catalyst was synthesized based on single-walled carbon nanotube (SWNT)-wrapped CoFe2O4 nanorods. The synergistic effect between CoFe2O4 nanorods and SWNTs can not only increase the oxygen vacancies and optimize the electronic structure of the composite but also facilitate the adsorption and stabilization of hydroxyl, which could significantly improve both the OER and HER performances. Besides, the addition of SWNTs would reduce the aggregating and tubes bundling in the composites and further improve the stability of the hybrid. All of the excellent performances indicated CoFe2O4/SWNTs as a promising bifunctional electrocatalyst for OER and HER, as well as overall water splitting.