In Situ Growth of Cobalt Nanoparticles Encapsulated Nitrogen-Doped Carbon Nanotubes among Ti3C2Tx (MXene) Matrix for Oxygen Reduction and Evolution

MXene with unique layered structure and rich chemical compositions has been extensively investigated for lithium-ion batteries, electrochemical capacitors, and hydrogen storage medium, but less attention has been paid to its electrocatalytic potential might due to nonideal activity. Here, an in situ growth strategy is developed to synthesize a new type of composite with carbon nanotubes (CNTs) supported on the surface of Ti3C2Tx MXene (Co/N-CNTs@Ti3C2Tx) as bifunctional electrocatalyst toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). By combining the X-ray photoelectron detection with synchrotron-based soft X-ray spectroscopic characterizations, the strong interfacial coupling and electron transfer are efficiently identified, which can effectively facilitate the bifunctional electrocatalytic performance of Co/N-CNTs@Ti3C2Tx toward ORR and OER in alkaline solution. The present strategy provides a facile route for the design of the hybrids of CNTs and MXene for bifunctional electrocatalysis.