Preparation Of Fe-C/Al₂O₃ Single-atom Catalyst And Investigation Of Their Catalytic Performance In Catalytic Hydrolysis Of CS₂

Carbon disulfide（CS₂）is widely found in chemical gases produced from coal,oil,and natural gas.Even the production of 1 ppm of CS₂ during the production process can aggravate reactor corrosion and cause catalyst deactivation during production.Therefore,research and development of stable and efficient catalytic materials for removing CS₂ produced in industrial production processes is one of the effective ways to extend the service life of equipment and ensure efficient industrial production.Single-atom catalysts（SACs）with high catalytic activity and metal utilization have a leading role in the chemical industry beyond traditional heterogeneous catalysis.Since the advent of SACs,it has been a hot research object in the field of catalysis.Compared with traditional heterogeneous catalysts,SACs have been used in a variety of conventional chemical reactions such as oxygen reduction reactions（ORR）,CO₂catalytic reduction conversion,water gas shift,and photocatalytic H₂ precipitation.Shows excellent catalytic activity.However,SACs have not been studied in terms of gaseous pollutant purification and catalytic hydrolysis reactions.In this thesis,the unconventional high-hazardous toxic gas CS₂ is used as the research object.SACs are prepared by different synthetic methods.The SACs concept is effectively applied to the catalytic hydrolysis and removal of CS₂.The successfully prepared Fe-C/Al₂O₃ single-atom catalyst has more excellent catalytic hydrolysis activity than Fe₂O₃-C/Al₂O₃ with metal oxide as the active component.The research of this paper includes the following parts:1、Extending the theory of single-atom catalysis to the catalytic hydrolysis system of CS₂.Synthesis of single-atom catalysts in one step.Encapsulated precursor formed by reaction of nitrate with dimethylimidazole and coated with active metal precursor.The effects of the types and contents of nitrate ligands,the types and contents of metal active components,and the calcination temperature were systematically investigated.Fe-C/Al₂O₃ catalyst with CS₂ catalyzed hydrolysis activity was successfully prepared.The experimental results were:C₁₅H₂₁Fe O₆:C₄H₆N₂:Al（NO₃）₃·9H₂O=1:18:90（molar ratio）is the optimal ratio of Fe-C/Al₂O₃ preparation,and 600 Celsius system is the optimal roasting temperature.Under the optimal preparation conditions,the 100%removal time of CS₂ is 270min.Its catalytic activity for the hydrolysis of CS₂ is much stronger than that of Fe₂O₃-C/Al₂O₃ with metal oxide as the active component.The high-angle-annular-dark-field scanning transmission electron microscopy（HAADF-STEM）and synchrotron X-ray absorption fine structure（XAFS）were used to characterize the Fe single-atom structure of Fe-C/Al₂O₃ catalyst and the coordination form of Fe Nx.2、The Fe-C/Al₂O₃ catalyst was optimized by using a solvothermal method based on the optimal type and content of nitrate ligands and the type and content of metal active components in a one-step method.The effects of solvothermal reaction temperature,reaction time and calcination temperature of solvothermal Fe-C/Al₂O₃catalyst were investigated.The experimental results were:the optimal solvothermal reaction temperature is 160 Celsius system,the reaction time is 4h,and the roasting temperature is 600 Celsius system.Under the optimal preparation conditions,the 100%removal efficiency of CS₂ was increased to 330min.BET,XRD,and XPS characterization results show that the Fe-C/Al₂O₃ single atom prepared by the solvothermal method has a better specific surface area（336 m²/g）and total pore volume（0.18 cm³/g）.And the Fe-C/Al₂O₃ single-atom catalysts prepared by the dissolution heat method has the best graphitization degree and finer structure.In Fe-C/Al₂O₃catalyst,N exists in pyridine nitrogen and pyrrole nitrogen,and C exists in C-C and C-N is the key to improve catalysis.3、Considering the industrial application of the Fe-C/Al₂O₃ catalyst,the effects of reaction temperature,water content,space velocity,and inlet concentration on the catalytic hydrolysis reaction of CS₂ were investigated,and the most favorable process conditions for the reaction were obtained.The experimental results are as follows:150Celsius system reaction temperature,12.5%relative humidity,a space velocity of 3500h^-1,and CS₂ inlet concentration of 250mg/m³ have the best CS₂ catalytic hydrolysis effect.