Photocatalytic Nitrogen Fixation Performance Of Nanometer CeO₂ And CeO₂/BiOCl Catalysts

The Haber-Bosch industrial synthesis of ammonia promoted the rapid development of agriculture and economy.However,this process is realized under very serious conditions,which not only consumes a lot of fossil energy,but also produces a lot of carbon dioxide,causing serious greenhouse effect.The novel photocatalytic nitrogen fixation is considered to be a very promising method for ammonia synthesis,but activation of nitrogen triple bond is still one of the primary considerations in photocatalytic nitrogen fixation due to the high bond energy of nitrogen triple bond(960 KJ·mol^-1).The defect states on the surface of catalyst（such as oxygen vacancy）is proved to promote the photocatalytic nitrogen fixation.This paper takes advantage of oxygen vacancy to obtain the nitrogen fixation ability of CeO₂ catalyst in acidic condition.On basis of this,CeO₂ is further modified to obtain a photocatalytic with catalytic nitrogen fixation performance under neutral conditions.The main research contents are as follows:（1）Considering that the cerium dioxide of nanorods has two valence states of Ce³⁺and Ce⁴⁺,the cerium dioxide of nanorods also has the characteristics of abundant oxygen vacancy,and the cerium dioxide has a strong redox capacity under acidic conditions.Therefore,in this part,the acidic solution is used as the reaction environment,and the performance of CeO₂catalytic nitrogen fixation is studied in acidic solution.（2）Nanorods cerium oxide have catalytic nitrogen fixation activity under acidic conditions.However,acidic environment is not conducive to practical application and the nitrogen fixation efficiency is low.At the same time,Ce³⁺changed into Ce⁴⁺is a consumption process,so the CeO₂ should be modified to achieve the recycle of Ce³⁺.In this part,BiOCl with abundant oxygen vacancy was selected to modify CeO₂.The composite photocatalyst CeO₂/BiOCl with different mass fraction and rich oxygen vacancy was synthesized by simple stirring at room temperature.Further photocatalytic nitrogen fixation experiments showed that the highest NH⁴⁺generation rate of 16.5%CeO₂/BiOCl composite catalyst was 245μmol/L/h.Which is higher than CeO₂ and BiOCl.