Research On The Appiication Of Classical Transition Metal Complexes For Catalytic Oxidation Reactions Of CO And VOCs

In the context of the era when all countries are working hard to cope with climate change,accelerate the transformation of green industries,and build a clean and beautiful world.Improving the efficiency of green energy use and controlling environmental pollution have aroused widespread concern among scientific researchers.So far,the preferential CO oxidation（CO-PROX）reaction and the volatile organic pollutant oxidation（VOCs）reaction have always been research hotspots.The former,as an important model reaction for hydrogen purification,is crucial to the utilization and development of hydrogen energy.And the latter has far-reaching significance for atmospheric environmental protection.How both types of catalytic oxidation reactions face the problems of low reactivity,low stability and high price of catalysts,which are urgently needed to be solved.Transition metal complexes are well known for their cheap price,huge storage capacity,adjustable electron density and variable valence,and they have potential for application in catalytic oxidation in the future.Therefore,this article takes transition metal composites as the research object,and explores the composite ratio,oxygen vacancy and electronic structure of transition metal composites to improve the catalytic performance of CO-PROX reaction and VOCs reaction.The specific research content is as follows:Synthesis of PtO_X-FeCP composite catalyst with platinum-iron alloy interface.PtO_Xwas supported on FeCP by one-step light deposition method,and a catalyst with platinum-iron alloy interface was synthesized.For catalysts with different proportions of PtO_X-FeCP,the analysis of HRTEM,XPS,ICP,and BET found that the light deposition precipitation method can achieve the deposition of Pt ions on the surface of the carrier,and platinum and iron deposited on the edge of the carrier.An alloy is formed between platinum and iron.The Pt loading content directly affects the catalytic activity of the catalyst for the CO-PROX reaction.It is found that 3wt.%PtOX-Fe PC catalyst has the best catalytic performance in the regulation of PtOX-FeCP catalyst ratio.It has the highest CO conversion rate（99%）at 155℃.After three cycles of testing,the performance of the 3wt.%PtOx-Fe PC catalyst shows a weak activity loss in the low temperature section,but the high temperature section can still maintain a high CO conversion rate.Construction of CeO₂/CuO_x-g-C₃N₄ composite material with high catalytic activity of CO-PROX reaction.The Cu⁺content in CeO₂/CuO_x-g-C₃N₄ composites can be effectively controlled by adjusting the contents of g-C₃N₄.A series of characterization of the catalyst proved that:g-C₃N₄ is beneficial to produce the reduced Cu⁺species and to promate the dispersion of copper and cerium species,thereby enhancing the catalytic activity of the catalyst in the CO-PROX reaction.When g-C₃N₄ is combined with CeO₂/CuO_x,the catalytic performance is the best when g-C₃N₄ accounts for 18%of the total mass.At 110℃,CO has reached full conversion and has a wide temperature window（110-210℃）.Construction of CeO₂/Cu_xO/Cu composites with foam mesh substrate.The amount of Ce（NO₃）₃ impregnated in CFO during the preparation of CeO₂/Cu_xO/Cu is very important to the interface structure.By increasing the amount of impregnated Ce（NO₃）₃,the Cu/Ce synergy at the CeO₂/Cu_xO interface can be effectively adjusted.The results show that changing the amount of impregnated Ce（NO₃）₃ can tune the CeO₂ content and control the electron transfer at the CeO₂/Cu_xO interface,thereby changing the defect concentration on the Ce-C-C surface.During the synthesis and regulation of Ce-C-C,Ce-C-C-1.5 has the best catalytic performance.In the dark reaction of 800ppm benzene,Ce-C-C-1.5 can adsorb 81.09% of benzene in 20 minutes,which is benefited to the mesoporous structure of Ce-C-C-1.5.Ce-C-C-1.5 under simulated sunlight,800ppm benzene can degrade 99.49%in 20 minutes,and has a mineralization rate of 100%.The excellent photothermal catalytic oxidation activity of benzene benefited from the synergy between the two redox pairs Ce³⁺/Ce⁴⁺and Cu⁺/Cu²⁺,which enriches a large number of CuO_x active species on the surface of the catalyst.The oxygen vacancies induced by Cuⁿ⁺and Ce³⁺also provide abundant active sites and pathways for oxygen adsorption,activation and migration for photothermal catalytic oxidation of benzene.