Facile synthesis of the encapsulation of Co-based multimetallic alloys/oxide nanoparticles nirtogen-doped carbon nanotubes as electrocatalysts for the HER/OER

The pivotal challenge of electrocatalysis remains the development of highly effective electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In this work, a universal strategy of preparing the encapsulation of Co-based multimetallic alloys/oxide nanoparticles in nitrogen-doped carbon nanotubes (named CoM@CNTs, M = Ni/Mn/Fe) was induced by annealing mixtures of the as-synthesized precursor, ethanol and different metallic acetates, including binary CoNi@CNTs, ternary CoNi/MnO@CNTs and quaternary CoNiFe/MnO@CNTs. By virtue of its unique structure with a high electrical conductive network based on CNT substrates, abundant catalytic active sites supplied by multimetallic nanoparticles and protection against nanoparticle corrosion by N-doped carbon layers, the as-synthesized CoNiFe/MnO@CNTs electrocatalyst has remarkable HER properties with a low overpotential of 122 mV and OER activity with a low overpotential of 275 mV at 10 mA cm−2 and excellent stability and durability under long-term testing in alkaline solutions. Therefore, this strategy will provide a new route for fabricating multimetallic-based CNTs as HER/OER electrocatalysts with excellent stability and high catalytic activity.