Preparation Of Titanium Dioxide-based Catalyst And The Research Of Formaldehyde

Formaldehyde is a kind of volatile toxic gasous,long-term exposure can induce cancer,which has attracted the attention of a large number of researchers.Catalytic oxidation is a method that has been studied extensively and does not cause secondary pollution.However,using the method of catalytic oxidation to remove formaldehyde at room temperature,developing a suitable catalyst is the key to solving the problem.As we all know,titanium dioxide is a commonly semiconductor material with photooxidation ability,large specific surface area,and good chemical stability.However,the band gap energy is relatively wide and only responding to ultraviolet light,which limits its application under natural condition.The study found the activity and stability of the catalyst can be improved by different modification methods,achieving good catalytic effect of formaldehyde.In this paper,three modification methods were used to modified titanium dioxide-based catalyst,such as C,N-TiO2,r-C,N-TiO2,Fe-TiO2,Ag@Fe-TiO2,Cu-TiO2 and Ag@Cu-TiO2 catalysts,exploring its catalytic oxidation effect of formaldehyde at room temperature.The morphological structure and composition of the sample was analyzed by the characterization methods,such as XRD,SEM,XPS,UV-Vis,FT-IR,PL,TEM,ICP-OES,and nitrogen adsorption and desorption.The main content included three aspects which can be seen as follows;1.Preparation of C,N-TiO2 catalyst and r-C,N-TiO2 catalyst and the research of formaldehyde.The low temperature sol-gel method was used to prepare carbon-nitrogen-doped titanium dioxide(C,N-TiO2),and then a series of reduced carbon-nitrogen-doped titanium dioxide(r-C,N-TiO2)containing different oxygen vacancies was prepared by sodium borohydride reduction,the catalytic effect of C,N-TiO2 and r-C,N-TiO2 was explored.The result showed that the effect of C,N-TiO2 was better than ordinary titanium dioxide,and r-C,N-TiO2 was better than C,N-TiO2.The best catalytic oxidation activity can reduce the concentration of formaldehyde gas to 0.06 Mg/M3(GB 0.08 mg/m3),which still showed a good catalytic oxidation effect after five rounds of cyclic experiments.2.Preparation of Fe-TiO2 catalyst and Ag@Fe-TiO2 catalyst,and the research of formaldehyde.A series of Fe-TiO2 catalyst was prepared by ultrasonic hydrothermal method and then used to catalytic oxidation of formaldehyde at room temperature.The result showed that the catalytic activity of Fe-TiO2 was improved compared with P25,but the final formaldehyde concentration was still higher than the national standard.In order to improve the catalytic activity of Fe-TiO2 catalyst,different concentration of Ag was loaded on Fe-TiO2 to prepare Ag@Fe-TiO2 catalyst,which obtained a good catalytic oxidation effect of formaldehyde.The final formaldhyde concentration was 0.05 mg/m3,and still below 0.08 mg/m3 after four rounds of tests,realizing the catalytic oxidation of formaldehyde at room temperature for a long time.3.Preparation of Cu-TiO2 catalyst and the research of formaldehyde.Using CuCl2 as the Cu source and ascorbic acid as the reducing agent,a series of copper-doped titanium dioxide catalysts(Cu-TiO2)containing higher active oxygen and different copper species were prepared for the catalytic oxidation of formaldehyde at room temperature.The results showed that when the copper doping amount was 3.0%,the catalytic effect of formaldehyde was the best,and the concentration of formaldehyde was 0.04 mg/m3.After four cycle tests,the formaldehyde degradability of Cu-TiO2 was still belowed 0.08 mg/m3.Compared with other related catalyst,the 3.0%Cu-TiO2 catalyst was also behaved better catalytic activity.