Transition Metal Oxides Nanomaterials For Enhanced Stable Simultaneously Catalytic Removal Of Formaldehyde And Ozone

Formaldehyde is a common pollutant in the indoor environment,which has great harm to human body.It will seriously affect the physical and mental health and efficiency of the occupants.Therefore,more and more attention is paid to the removal of formaldehyde by catalytic oxidation.Meanwhile,ozone is a highly oxidizing gas.Under ideal reaction conditions,ozone decomposition can produce reactive particles with high activity.By destroying the chemical bonds in organic compounds,ozone can achieve the purpose of removing pollutants.Therefore,the study and use of the coupling effect of catalyst-ozone to efficiently remove the formaldehyde can efficiently remove the ozone.Transition metal oxide has a strong catalytic activity for the catalytic degradation of organic compounds,and the price is relatively low,so it has become the focus of the field of environmental purification.In this paper,manganese based oxide catalyst C@MnO_x was prepared by using carbon spheres as template.The catalytic performance of simultaneous catalytic removal of formaldehyde and ozone was investigated.Mesoporous Nickel oxide was prepared on silica template.The catalytic performance of simultaneous catalytic removal of ozone and formaldehyde and thermal catalytic removal of formaldehyde was investigated.XRD,TEM,BET,ICP,TPD,TPR,Raman,XAS,XPS and in situ DRIFT were used to characterize them,and the mechanism of catalytic oxidation of formaldehyde was studied in order to achieve the goal of efficient catalytic degradation of formaldehyde.The results of the study show that:1.Manganese based oxide catalysts prepared with carbon spheres as template can produce low coordination Mn²⁺in situ after calcination in inert atmosphere.The core shell structure C@Mn O composite nanomaterial catalyst has the adsorption centers and reactive sites.The amount of Mn Ox load will affect the adsorption of the catalyst,the catalyst of strong adsorption of formaldehyde has high removal rate,and the C@MnO_x calcined in inert atmosphere relative can achieve higher CO₂selectivity.The C-Mn_0.06-550 catalyst can achieve 100%formaldehyde and ozone removal rate and 100%CO₂ selectivity when 60ppm formaldehyde,180ppm ozone and relative humidity are 50%.2.Unsaturated lamellar Mn O is loaded on the surface of carbon spheres,forming a layered core-shell structure,which can achieve stable adsorption and concentration,ozone decomposition and formaldehyde removal.Low coordination MnO plays an important role in simultaneous removal of formaldehyde and ozone,and the MnO layer on the surface protects the carbon core from being eroded by ozone.3.The Mesoporous Nickel based oxide catalyst prepared on silica template has higher formaldehyde conversion and CO₂ selectivity than formaldehyde prepared by citric acid in the simultaneous removal of formaldehyde and ozone.The three-dimensional mesoporous NiO sample prepared by KIT-6 template can achieve 100%formaldehyde and ozone removal rate and 100%CO₂ selectivity when 60ppm formaldehyde,180ppm ozone and relative humidity are 50%.Without ozone,the three-dimensional mesoporous Ni O sample prepared with KIT-6 as template can achieve 13%formaldehyde conversion rate under dry air,while in wet air(RH=50%),the formaldehyde conversion rate is further increased to 26%.4.The surface alkali metal sodium modified NiO can promote hydroxyl regeneration,surface hydroxyl regeneration and improve the activity in the thermal catalytic reaction,but it does not show the activity improvement in ozone reaction.The adsorbed oxygen species on the surface of the catalyst and the low coordination Ni²⁺play an important role in improving the activity of the ozone reaction.