Preparation And Photocatalytic Performance Of Nano TiO₂ Self-cleaning Inorganic Decorative Panels

Due to the long-term influence of atmospheric pollution,the surface of building fa（?）ade decoration materials is highly susceptible to stains,wear and tear,aesthetic and durability degradation and other problems.The self-cleaning function can effectively solve these problems and has good market prospects and research value.In this paper,inorganic decorative panels with self-cleaning function were prepared by layering,spraying,infiltration and vacuum adsorption methods,using anatase nano-Ti O₂（NT）as the photocatalytic material.The self-cleaning function and photocatalytic performance of the decorative panels were investigated by testing the degradation rate of the decorative panels against pollutants such as rhodamine B solution（Rh B）,soy sauce and NO gas.Details of the study and the results are as follows.（1）The NT self-cleaning decorative panels were prepared by the layering method.The influence of NT particle size and doping amount on the compressive strength and photocatalytic performance of the decorative panels was studied,and the thickness of the NT surface layer was determined.Under the same conditions of NT particle size,the compressive strength of the decorative panels increased and then decreased with the increase of NT doping,and the degradation rate of Rh B increased with the increase of NT doping.Under the same conditions of NT dosing,the compressive strength of decorative panels increases with the increase of NT particle size,and the degradation rate of Rh B decreases with the increase of NT particle size.The compressive strength of the decorative sheet decreases with increasing thickness of the NT surface layer.Considering the compressive strength and photocatalytic efficiency,the optimum process parameters for the preparation of self-cleaning decorative panels by the layering method are:25 nm NT particle size,5%doping,and 1/7 of the thickness of the decorative panel.（2）NT self-cleaning decorative panels were prepared by the spraying,immersion and vacuum adsorption loading processes.The effects of the loading process and suspension loading concentration on the photocatalytic performance of the self-cleaning decorative panels were investigated.The degradation rate was 94%using the spraying,immersion and vacuum adsorption methods,but the decorative plate prepared by the vacuum adsorption method had the highest Ti O₂ loading depth.The degradation rate of Rh B was only 10%for the decorative plates with 3%and 0.5%concentration of NT suspension prepared by the vacuum adsorption method.Therefore,considering the photocatalytic performance and the economics,the self-cleaning decorative panels were prepared by vacuum adsorption of NT suspensions at 0.5%.（3）The effect of NO concentration and water content on the NO degradation rate of decorative panels was investigated by preparing self-cleaning decorative panels by the layering method.As the water content increased,the NO degradation rate of the decorative panels showed a trend of increasing and then decreasing.With the increase of NO concentration,the degradation rate of NO by the decorative panels increased,but the total degradation rate of NO by the decorative panels decreased.（4）The photocatalytic durability of NT self-cleaning decorative panels was tested under different effects using long-term exposure tests,washout tests,immersion tests and abrasion tests.The durability performance of the decorative panels prepared by the layered method was the strongest,followed by vacuum adsorption,with the infiltration and spraying methods having the worst durability performance.Taking into account the photocatalytic performance,durability and effective utilization of Ti O₂ of the decorative board,it is recommended to use the vacuum adsorption method to prepare the self-cleaning decorative panels.