The Performance Of Nitrogen-Containing Carbon-Based Materials As Electrocatalysts In Oxygen Reduction Reaction And Glucose Oxidation Reaction

It is widely accepted that the decrease of the storage of the fossil fuel and the environmental pollution have hindered the development of society.Energy-saving and environmental protection technologies are effective ways to resolve those problems.Among of these technologies,electro-catalysis has attracted much attention due to its being environment-friendly and high efficiency.In this thesis,based on the rich experience of synthesis of macrocyclic compounds like porphyrin in our group,three kinds of nitrogen-containing carbon-based non-precious metal electrocatalysts were prepared and studied in the performance of oxygen reduction reaction?ORR?and glucose selective oxidation reaction?ORG?respectively.The main research contents are as follows:?1?In order to explore the effect of the active center of the porphyrin macrocycle on the oxygen reduction reaction?ORR?.The free ligand tetramethoxyphenyl porphyrin?MTPP?with carbon black material?KB,XC,BP?as carrier,tetramethoxyphenyl cobalt porphyrin?CoMTPP?and supported metal Co nanoparticles was selected.The active components were compared to study the effect of complexed Co atoms and supported Co nanoparticles on ORR activity.Co nanoparticles were loaded on MTPP to assess the function of Co-N₄-C which resulted from heat treatment of CoMTPP X ray powder diffraction?XRD?,transmission electron microscope?TEM?,cyclic voltammetry?CV?and linear sweeping voltammetry?LSV?are employed to characterize the properties of catalysts.It is found that KB is the best catalyst support and the optimal mass ratio of KB to catalyst is 9:1.Compared with Co/MTPP,Co-N₄-C shows better performance and its electron transfer number for ORR is 3.2 calculated from Koutecky–Levich?K-L?plots.It is proved that the reaction process is a process that tends to a four-electron reaction.?2?In order to distinguish the roles of four types of nitrogen species in oxygen reduction reaction,the ketoamine condensation reactions between the ketone group of graphene oxide and amidogen of aniline and o-phenylenediamine were employed to generate-C=N-bond at the edge of graphene nanoplatelets,and then nitrogen-doped graphene nanoplatelets with pyrrolic N and pyridinic N rather than graphitic nitrogen were obtained by post thermal treatments.The resulting catalysts were characterized by X-ray diffraction analysis,X-ray photoelectron spectroscopy and electrochemical measurements.It is found that edge-selectively nitrogen-doped graphene nanopaltelets with nitrogen content of up to 4.28 atom%have been prepared.Nitrogen doping helps to improve activity of oxygen reduction reaction slightly,suggesting nitrogen doping at the edge of graphene does not contribute a lot to the enhancement of activity.The ORR activity test showed that the edge N and the supported cobalt nanoparticles were beneficial to the oxygen reduction reaction activity.?3?In this thesis,a peripheral nitro-substituted asymmetric sulfur-containing tetraaza-metal porphyrin was synthesized,and ¹H-NMR,UV-Vis,FT-IR,MALDI-TOF-MS was used to characterize the four kinds of sulphur-containing tetraazaporphyrinsMPhNO₂?SBu?₆Pz?M=Co,Zn,Ni,H₂?.Itisfoundthat PhNO₂?SBu?₆Pz shows the best according to CV.At the same time,CoPhNO₂?SBu?₆Pz is loaded to g-C₃N₄,which further improves the conductivity of the composite catalyst.CoPhNO₂?SBu?₆Pz/g-C₃N₄ catalysts were characterized by XPS,XRD and solid diffuse reflection,indicating that CoPhNO₂?SBu?₆Pz was successfully loaded into g-C₃N₄.Experimental results of glucose oxidation show that catalyst selectively oxidized glucose to gluconic acid,and the selectivity is up to 70%.In addition,the catalyst shows good stability in the cycling test,and the activity of catalyst remains relatively high after several cycles.