Study On Catalytic Performance Of Strontium Cobaltic Acid Controlled By Its Electronic Structure

Strontium cobaltite(Sr Co O_3-x,SCO)is a perovskite structure（ABO₃）material with catalytic activity found in both theoretical prediction and experimental observation.At normal temperature and pressure,the perovskite structure of Sr Co O₃（P-SCO）loses part of its lattice oxygen and changes to the structure of brownmillerite-Sr Co O_2.5（BM-SCO）.Similar to other perovskite materials,Sr Co O_3-xcan adjust its electronic structure and crystal structure by doping and loading,so as to overcome the problems of poor reaction kinetics,poor thermal stability and low catalytic activity in the catalytic process.In this paper,strontium cobaltite was used as the research object,and its electronic structure was adjusted by different methods to enhance the catalytic activity.The main contents are as follows:1、Strontium cobaltate was prepared by a method combining sol-gel and solid phase sintering,different calcination temperatures（700-900°C）and calcination time（4-10 h）were adjusted during the preparation process.The effect on the oxygen evolution reaction（OER）was observed and it was determined that the catalytic activity was the best when calcined at 800°C for 6 h.2、The transition metal element at the B site is the main catalytic active center of the perovskite structure material,and the adjustment of the A site element can affect the valence state of element,and then affect the catalytic activity of B site.In this paper,dual active centers were introduced by means of doping A and B sites respectively and co doping.Increase the content of transition metal unstable Co³⁺,Mn³⁺and lattice oxygen in the crystal structure,adjust the electronic structure,and improve its OER electrocatalytic performance.3、Due to the overlapping of O 2p and Co 3d orbitals in the Co-O bond in P-SCO,it has ideal thermal stability and high soot catalytic combustion activity.We have changed the electronic coordination structure of Sr Co O_3-xand prepared P-SCO by replaced the Sr²⁺with Y³⁺and Eu³⁺ions.Further P-SCO loaded with Ce O₂,increase the lattice oxygen content in the catalyst body,increase number of active sites,increase the contact area between the catalyst and soot particles,increase the dispersion of active components,and enhance the thermal stability of the catalyst,thereby improve its catalytic activity for soot combustion.4、Cobalt based heterogeneous catalysts have a large number of catalytically active sites that can activate hydroxyl radicals（·OH）,and theoretically have a high efficiency in catalyze the degradation of organic pollutants.However,its poor stability affects its application in photocatalytic degradation.Sr Co O_3-xhas unique reversible oxygen storage and oxygen release capabilities.In this paper,Ag nanoparticles（Ag NPs）were loaded onto the surface of Sr Co O_3-xby sol-gel method.Surface plasmon resonance improves the absorption of visible light by the catalyst,and avoids the disadvantages of difficult recovery in the practical use of heterogeneous catalysts due to the small size of Ag NPs,the electronic structure of Sr Co O_3-xis improved,the stability and reusability of the catalyst are improved,and in the Fenton reaction,the degradation efficiency of the organic pollutant methylene blue solution（MB）in sunlight is enhanced.