摘要
通过氮掺杂TiO_(2)(N-TiO_(2))浸渍蜂窝过滤器构建了一系列原型光催化空气净化器(AP(N_(x)-C_(y)))系统,并用于在UV-LED光(1 W)照射条件下光催化分解0.5-5 ppm甲醛(CH_(2)O)蒸汽.在上述催化过滤器系统中,Nx和Cy分别代表N/Ti摩尔比(0-20)和N-TiO_(2)浓度(2-20 mg mL^(-1)).光催化分解实验结果表明,AP(N_(10)-C_(10))的性能最好,其催化CH2O转化为CO_(2)的转化率最高,循环反应10次后CO_(2)产率仍达到89.2%,在干燥空气中的清洁空气输送速率为9.45 L min^(-1).N10-C10的电荷载流子寿命(τa:1.70 ns)优于其他样品(如纯TiO_(2)的电荷载流子寿命为1.37 ns),这表明N缺陷(No)有助于降低带隙(3.10 eV)和产生氧空位OVs-Ti^(3+),这与密度泛函理论(DFT)模拟结果一致.采用原位漫反射红外傅里叶变换、电子顺磁共振和DFT分析等多种方法研究了CH_(2)O的光催化氧化途径.结果表明,氧化过程涉及多个能量有利的中间步骤(例如CH2O以CH_(2)O_(2)的形式在TiO_(2)-OV{110}表面的桥连O/OH基团上发生放热共价吸附,随后通过催化脱氢/氧化反应直接生成CO_(2):CH_(2)O_(2)/HCOO^(-)+•OH→H_(2)O+CO_(2)).这些步骤与具有N杂质的{101}表面上化学活性Ti原子的态密度计算结果一致.预计No缺陷和OVs的存在将通过降低活化能垒来影响反应能量和中间产物,从而在加湿条件下实现有效的矿化.综上,本文为设计和构建先进的光催化系统,并用于环境空气中醛类挥发性有机物(VOCs)的有效矿化提供了新思路.
A series of proto-type photocatalytic air purifier(AP(Nx-Cy))systems are built with a nitrogen-doped TiO_(2)(N-TiO_(2))-impregnated honeycomb(HC)filter for photocatalytic decomposition of 0.5-5 ppm formaldehyde(FA:CH_(2)O)vapor under varying conditions and UV-LED light(1 watt).The binary codes of N_(x) and C_(y) in AP systems are used as the composition identifiers to represent N/Ti molar ratios(0 to 20)and N-TiO_(2)concentration(2 to 20 mg mL^(-1)),respectively.The AP(N_(10)-C_(10))is found as an optimum unit with the highest capability to boost the catalytic conversion of CH_(2)O to CO_(2)(yield=89.2%over 10th cycles and the clean air delivery rate(CADR)of 9.45 L min^(-1)in dry air).The superior charge carrier lifetime(τa:1.70 ns)of N_(10)-C_(10) over others(e.g.,1.37 ns for pure TiO_(2))should indicate the influential role of N-defects(No)in reducing the bandgap(3.10 eV)and in creating defect-related oxygen vacancy(OVs-Ti^(3+))states as predicted by the density functional theory(DFT)simulation.The photocatalytic oxidation pathway of CH_(2)O,when assessed by diverse approaches(e.g.,in-situ diffuse reflectance infrared Fourier transform,electron paramagnetic resonance,and DFT analyses),is found to involve several energetically favorable intermediate steps(such as exothermic covalent adsorption of CH_(2)O to bridged O/OH groups on TiO_(2)-OV{110}surface in the form of CH_(2)O_(2)followed by catalytic dehydrogenation/oxidation reactions to yield CO_(2)through direct route:CH_(2)O_(2)/HCOO-+•OH→H_(2)O+CO_(2)).These steps are supported by the calculated density of states(DOS)for chemically active Ti-atom on{101}surface with N-impurity.The presence of No-defects and OVs is expected to influence the reaction energetics and intermediates for efficient mineralization in humidified conditions by lowering the activation barriers.This study offers valuable insights into the design and construction of an advanced photocatalytic system for efficient mineralization of aldehyde VOCs in ambient air.
作者
Dae-Hwan Lim
Aadil Bathla
Hassan Anwer
Sherif AYounis
Danil WBoukhvalov
Ki-Hyun Kim
Dae-Hwan Lim;Aadil Bathla;Hassan Anwer;Sherif AYounis;Danil WBoukhvalov;Ki-Hyun Kim(Department of Civil and Environmental Engineering,Hanyang University,222 Wangsimni-ro,Seongdong-Gu,Seoul 04763,Korea;Department of Environmental Engineering,National University of Sciences and Technology,H-12,Islamabad 44000,Pakistan;Analysis and Evaluation Department,Egyptian Petroleum Research Institute,Nasr City,Cairo 11727,Egypt;College of Science,Institute of Materials Physics and Chemistry,Nanjing Forestry University,Nanjing 210037,Jiangsu,China;Institute of Physics and Technology,Ural Federal University,Yekaterinburg 620002,Russia)
基金
This work was supported by a grant from the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(MSIT)of the Korean government(2021R1A3B1068304).The authors also acknowledge the support provided by a grant from the NRF funded by MSIT of the Korean government(RS-2023-00243840)and Brain Pool program(RS-2023-00222393).D.W.Boukhvalov acknowledges support from Jiangsu Innovative and Entrepreneurial Talents Project,and the Ministry of Science and Education of Russian Federation(FEUZ-2023-0013).
关键词
光催化蜂窝过滤器
甲醛
氮掺杂TiO_(2)
密度泛函理论计算
催化反应途径
空气净化
Photocatalytic honeycomb filter
Formaldehyde
Nitrogen-doped TiO_(2)
Density functional theory calculations
Catalysis reaction pathways
Air purification
