Construction Of "Doped Carbon Layer Coated Rare Earth Oxide" Composite Electrocatalytic Material Based On Carbonized Polyaniline And Its Performance In Oxygy Reduction Reaction

So far,the best catalyst for catalytic oxygen reduction?ORR?is Pt-based catalysts.However,the commercialization of fuel cells is limited by the limited reserves,short service life and prone to poisoning of Pt-based catalysts.Therefore,research and development of efficient,stable,abundant and non-polluting non-precious metal catalysts are the main tasks for the future development of fuel cell technologies.Rare earth elements have unique electronic configurations,making rare earths have good electronic and catalytic properties.And many rare earth elements have been used in the preparation of catalysts and have achieved the desired results.Among them,rare earth oxides as a non-Pt catalyst have shown promising applications in ORR catalysis,which has attracted the interest of researchers.The main purpose of this paper is to prepare high-efficiency,low-cost non-noble metal catalysts for ORR.Combining the excellent properties of rare earth oxides and conductive polymers,a high performance catalytic system of rare earth oxide coated with doped carbon layer is expected.In these three parts,physical tests were used to characterize the prepared catalysts.At the same time,their electrochemical performances were examined using electrochemical testing methods.The thesis consists of three parts as follows:Part ?: Sm₂O₃ nano-oxide embedded in carbon material as an efficientelectrocatalyst towards oxygen reduction reactionDue to its unique electronic configuration,rare earth oxides have aroused an upsurge of research in the field of fuel cells.Rare earth samarium is suitable for catalysts and accelerators due to its variable valence.In this chapter,Sm₂O₃-CN-1100 composite catalyst was prepared by simple hydrothermal method and in-situ polymerization,and its catalytic performance in oxygen reduction reaction was studied.The coupling effect between Sm₂O₃ and CN makes Sm₂O₃-CN-1100 have good stability and resistance to methanol.In addition,the embedding structure of the catalyst enhances the connection between Sm₂O₃ and CN and facilitates the progress of the oxygen reduction reaction.This provides the new path for the application of other rare earth oxides in non-precious metal catalysts.Part ?: Bimetallic LaCuOx@CN catalyst for oxygen reduction reactionThe second chapter of this paper confirms that rare earth oxides have a certain catalytic activity for oxygen reduction,but there is still a big gap compared with the commonly used Pt/C catalysts.The literature reports that bimetallic composite oxides have better performance than single metal oxides.This chapter combines the advantages of dual metal oxides and carbon materials to successfully prepare a LaCuOx@CN composite catalyst and explore its catalytic performance in oxygen reduction reactions.Compared with the single metal rare earth oxide catalyst prepared in chapter 2,the ORR catalytic activity has been greatly improved.Compared with the Pt/C catalyst,LaCuOx@CN-900 has better stability and methanol resistance.Part ?: Encapsulated NdCuOx bimetallic nanoparticles with nitrogen doped carbon as an efficient electrocatalyst for oxygen reduction reaction in alkaline mediaAlthough the performance of prepared LaCuOx@CN-900 catalyst has been greatly improved,there is still a gap compared with the Pt/C catalyst.On the basis of the third chapter,a novel NdCuOx@CN-1000 composite catalyst was prepared by adjusting the composition of rare earth-transition metal bimetallic oxides.And it was used as a non-Pt catalyst for oxygen reduction reactions in alkaline media.Electrochemical results indicate that the NdCuOx@CN-1000 composite catalyst possesses comparable catalytic activity to that of Pt/C,even better methanol resistance and stability than Pt/C.This good performance is attributed to the strong interaction between NdCuOx and CN,as well as the NdCudouble metal oxides.