MXene-derived TiO₂@C Coupled With G-C₃N₄ For Removal Of NO In Flue Gas By Photocatalytic Activation Of Hydrogen Peroxide

As an environmentally friendly technology,photocatalytic technology has become a hot spot in the research on nitrogen oxides treatment.However,photocatalytic technology mostly focuses on the treatment of low-concentration（ppb）nitrogen oxides,but the ability of photocatalytic technology to treat high-concentration（ppm）nitrogen oxides in the industry is limited.The combined technology of photocatalytic oxidation and hydrogen peroxide oxidation technology to treat nitrogen oxides in industry has practical significance.In this paper,different forms of MXene-derived TiO₂@C/g-C₃N₄composite photocatalysts were prepared.The morphological structure,chemical composition,energy band structure,light absorption performance,photogenerated carrier separation efficiency and the performance and mechanism of removal of NO by photocatalytic activation of hydrogen peroxide were systematically analyzed.The research contents and conclusuions of this papar are as follows.1.Preparation and performance study of MXene-derived TiO₂@C/g-C₃N₄composite powder.TiO₂@C/g-C₃N₄ composite powder was prepared by a simple one-step calcination method to remove NO by photocatalytic activation of hydrogen peroxide.It was found that TiO₂@C/g-C₃N₄ composite powder showed good catalytic performance.The removal efficiency of NO by photocatalytic activation of hydrogen peroxide was as high as 94%.The efficiency was still about 80%even after 5 cycles,suggesting it had great cycle stability.According to the analysis of the light absorption performance and energy band structure of TiO₂@C/g-C₃N₄,the enhanced photocatalytic activity was due to the formation of Z-type heterojunction of TiO₂ and g-C₃N₄.Hydroxyl radical and superoxide radical were identified to play important roles in the process via the detection of active free radicals.Based on the above analysis,the mechanism of TiO₂@C/g-C₃N₄ for removal of NO by photocatalytic activation of hydrogen peroxide was proposed.2.Preparation and performance study of MXene-derived TiO₂@C/g-C₃N₄composite aerogel.The three-dimensional network TiO₂@C/g-C₃N₄ aerogel material was synthesized by the ice template method and calcination method,which was used to remove NO by photocatalytic activation of hydrogen peroxide.TiO₂@C/g-C₃N₄ aerogel had excellent removal efficiency of NO,with 90.7%of NO being removed even if the dose of catalyst used was only half of TiO₂@C/g-C₃N₄ composite powder.TiO₂@C/g-C₃N₄ aerogel had satisfactory cycle stability while keeping its three-dimensional structure intact.The removal efficiency after three cycles was still higher than 80%.Based on the energy band structure of TiO₂@C/g-C₃N₄ aerogel material,the separation behavior of photogenerated carriers,and the detection of free radicals,it was found that hydroxyl radical and superoxide radical played important roles in the photocatalysis process.The mechanism of TiO₂@C/g-C₃N₄aerogel for removal of NO by photocatalytic activation of hydrogen peroxide was proposed.