Photocatalytic Nitrogen Fixation Performance Of RuO₂/BiOCl And Homojunction Bi₂O₂CO₃ Catalysts

At the beginning of the 19th century,the establishment of the Haber-Bosch industrial synthetic ammonia method was of great significance to the rapid development of agriculture and economy,but industrial synthetic ammonia also caused harm to the environment.The new photocatalytic nitrogen fixation method is considered to be a very promising strategy and has attracted the interest of many researchers.However,nitrogen-nitrogen triple bond is one of the inert gases in nature,and the bond energy is up to 941 kJ/mol.The poor activation of nitrogen-nitrogen triple bond is a bottleneck problem faced by photocatalytic nitrogen fixation technology.The research indicates that the surface oxygen deficiency of the catalyst can enhance the adsorption and activation ability of the catalyst to nitrogen molecules,which is beneficial to the nitrogen fixation reaction.In this paper,two new strategies for constructing defect states are proposed.While obtaining high-efficiency photocatalytic nitrogen-fixing catalysts,it provides a theoretical basis for the development of new nitrogen-fixing catalysts in the future.The research of this thesis is as follows:?1?This part focuses on the reaction behavior of interface contact defects between different components of the composite catalyst during the nitrogen fixation reaction.The RuO₂/BiOCl composite catalyst with rich oxygen vacancies was synthesized by simple room temperature stirring method.The concentration of oxygen vacancy defects in the catalyst growth process was monitored by ESR characterization technique.It was proved that the interface between RuO₂ and BiOCl was rich.Defect state.The results of photocatalytic nitrogen fixation experiments show that the NH₄⁺formation rate of 0.2%RuO₂/BiOCl catalyst is up to 131.9?mol/L,which is 3.5 times that of pure BiOCl catalyst.The mechanism of nitrogen fixation performance enhancement is that the trapping state generated by the interface contact can promote the effective separation of electron-holes while improving the activation ability of nitrogen molecules.?2?This part focuses on the reaction behavior of amorphous materials in the photocatalytic nitrogen fixation process.In this paper,the ordered-disordered homojunction Bi₂O₂CO₃ catalyst was synthesized by the normal temperature rapid precipitation method using glyoxal with moderate reducing ability as the target material and initiator for generating oxygen vacancies.The nitrogen fixation experiments on the obtained catalyst show that the crystal structure Bi₂O₂CO₃ has almost no photocatalytic nitrogen fixation ability,while the ordered-disorder homojunction Bi₂O₂CO₃ catalyst has strong photocatalytic nitrogen fixation capacity?52.3?mol/L?.The reasons for the improvement of photocatalytic performance are?1?amorphous Bi₂O₂CO₃ can effectively activate nitrogen molecules;?2?ordered-disorder homojunction can effectively improve the separation efficiency of electron-hole pairs.