Mechanism Of NO_x Removal By Bamboo Charcoal Supported Oxygen Vacancy BiOI/BiOCl Composite Photocatalyst

Nitrogen oxides?NO_x?,as a common pollution gas,lead to environmental pollution problems such as haze,photochemical smog,acid rain and other environmental problems.The concentration of NO_x in the atmosphere has been increasing since 2017.Therefore,the development of efficient and economical technology to remove NO_x pollutants has become an important issue in the current scientific community.Existing methods,such as selective catalytic reduction?SCR?,selective non catalytic reduction?SNCR?and other denitrification methods,have been widely used,but these methods are costly and easy to produce two times of pollution.Therefore,the use of solar energy to treat NO_x pollutants by photocatalyst is an efficient,economical and energy saving method.Therefore,photocatalysis is a promising and attractive alternative technology.Bismuth oxide has attracted more and more attention due to its suitable energy band location and ability to utilize sunlight.However,the lack of electron hole separation efficiency,low active sites and poor degradation efficiency of pollutants restrict the practical application of bismuth oxide materials.In order to further improve the photocatalytic properties of bismuth halide,a large number of previous studies have been carried out,such as morphology control,metal or nonmetal doping,oxygen vacancy modification,but most of these studies have been modified for BiOCl,BiOI and other pure photocatalysts,and the oxygen vacancy?Oxygen Vacancy,OV?is modified.There are few reports on BiOI/BiOCl denitrification.BiOI/BiOCl photocatalyst with oxygen vacancies were successfully synthesized by solvothermal method using bamboo charcoal as the carrier.The effect of temperature and light on the denitrification process was studied.The optimum denitrification efficiency was 73%when the xenon lamp power is 500W and the temperature was 30?.The denitrification mechanism of composite photocatalyst was studied by means of SEM,XPS,XRD,PL and UV-vis analysis.After OV modification,the specific surface area and pore capacity of BC was enhanced obviously.Meanwhile,the functional groups of C=O and-COO were broken down into C-O functional groups,which improved material's physical and chemical adsorption properties.It can be concluded that OV modification increases the photocatalytic activity sites,reduces the recombination rate of electron hole pairs,and thus improves the photocatalytic degradation efficiency of NO.The main research content is as follows:?1?Oxygen vacancies?OV?BiOI/BiOCl photocatalysts were prepared by solvothermal method using bamboo charcoal as carrier.The influence of temperature and light on the denitrification process was studied.When the deuterium lamp power was 500W and the temperature was 30°C,the best denitrification efficiency was 73%.?2?The results of SEM,XPS,XRD,PL,DRS and other characterization methods indicate that BiOI_0.5Cl_0.5 is successfully loaded on the surface of bamboo charcoal.OV modification can increase the specific surface area and pore volume of bamboo charcoal and improve its physical adsorption capacity.At the same time,the C=O double bond and the-COO form of the acidic functional group are decomposed into CO functional groups to improve the chemical adsorption performance of the sample;and the OV modification increases the photocatalytic active sites and reduces the probability of electron hole pair recombination,thereby improving the Photocatalytic degradation efficiency of NO.?3?By comparing the effect of I:Cl ratio,bamboo charcoal loading,calcining temperature and calcining atmosphere on the denitrification efficiency,the optimal preparation conditions of the material are:I:Cl ratio 0.5:0.5,bamboo charcoal loading10g,calcination temperature 300°C,the calcination atmosphere was N₂:O₂=9:1.?4?BC/Bi-OV has good reproducibility,and its catalytic activity still maintains a high value after 4 times of recovery.It shows that BC/Bi-OV has the prospect of industrial application and has in-depth research value.