Mesoporous Carbon Nanotubes Rich In Pyridinic N And Their Composite Electrocatalysts:Structure Engineering And Electrocatalytic Performance

Carbon nanotubes（CNT）have broad application prospects in the field of electrocatalysis due to their great loading capacity,excellent chemical stability and low cost.However,the surface of pure CNTs shows the lack of active sites,which requires certain modification methods to improve the electrocatalytic performance.It has been found that heteroatomic pyridinic N doped in edge/mesoporous structures is the dual active site of ORR and OER.In addition,a lot of studies have shown that the composite material composed of transition metal sulfide nanosheets and N-doped carbon nanomaterial will show excellent HER electrolytic performance due to the new active site generated by electron coupling at the interface.Herein,CNT rich in pyridinic N and mesoporous structure were designed and synthesized,and then used for oxygen electrocatalysis.The characterization of the materials shows that the mesoporous edges on the surface of CNT not only promote the mass transfer process,but also facilitate the doping of active site pyridinic N.Electrochemical tests indicate that the catalysts we prepared show significant enhancement of catalytic activity in alkaline medium,and realize efficient bifunctional electrocatalysis.The ORR half-wave potential reaches 0.84V（vs.RHE）and the OER overpotential reaches 0.36V.At the same time,it shows good charge and discharge performance and cycle stability in the application of Zinc-air battery.Subsequently,MoS₂/NL-CNT composite catalyst with good dispersion and rich Mo-N bond was prepared on the basis of the prepared carbon nanotubes with high N content.Through the analysis of morphology,structure and electrocatalytic performance,it is found that the dispersion effect of carbon nanomaterials on the sulfide nanosheets fully exposes the catalytic sites at the edge of the nanosheets.At the same time,the metal atom at its interface has a chemical coupling effect with N atom,which becomes a new catalytic center and jointly improves HER catalytic performance.