缺陷型碳纳米管担载过渡金属催化氧化VOCs的性能和机理研究

Catalytic oxidation technology can be considered as one of the most effective and economical alternatives for the abatement of VOCs. Metal oxide as the promising catalysts for the catalytic oxidation of VOCs has been attracted widely attention in the field of environmental catalysis, but its activity is still inferior to precious metal catalyst. It is well known that the pros and cons of the catalyst performance decide the catalytic efficiency and running costs. Therefore, how to improve the activity of the metal oxide catalyst is an urgent problem to be resolved for the promotion of the VOCs catalytic oxidation. In the project, we would improve the catalytic activities of the supported metal oxide in the catalytic oxidation of VOCs by the effect of the surface structure of carbon nanotubes. We will synthesize the incomplete bonding defects, N-doped chemical defect structure and pentagon defects on the surface of CNTs, and we will investigate the chemical and electronic properties of the defects. Combined with the characteristics of the catalytic oxidation of VOCs, the supported Fe, Cu, V, Co and Ni on CNTs would be prepared by impregnation with the aid of the ultrasonic method and hydrothermal method. The effects of the incomplete bonding defects, N-doped chemical defect structure and pentagon defects on the redox, acidic/basic property and the concentration of the surface adsorb oxygen and the lattice oxygen will be investigated, and the relation of the defects and the catalytic performance will be concluded to construct the highly effective catalysts. We will study the kinetics of VOCs catalytic oxidation and the catalytic mechanism on the prepared catalysts, which could supply the theory to design highly effective catalysts for the abatement of VOCs.

催化氧化技术是去除挥发性有机物(VOCs)最有效的途径之一。金属氧化物催化氧化VOCs 一直是环境催化领域的研究热点。而催化剂性能的优劣对催化效率和运行成本有着决定性的影响。因此，如何提高金属氧化物催化剂的活性是推广催化氧化VOCs技术的重要因素。本项目提出利用缺陷型碳纳米管的电子态调变担载的金属氧化物的电子态近而影响催化剂氧化VOCs的催化性能。本研究将发展碳纳米管表面结构修饰技术，可控制备不饱和键缺陷、N掺杂型化学缺陷和五元环拓扑缺陷碳纳米管，研究缺陷的化学性质和电子特性。通过超声浸渍、水热等方法，在缺陷型碳纳米管表面负载Fe、Cu、V、Co、Ni过渡金属氧化物，揭示缺陷型碳纳米管对复合催化剂表面电子态的调变规律。研究VOCs在催化剂上反应动力学，揭示催化机理，确定复合催化剂表面电子态与催化剂催化性能和催化机理的定性、定量关系，为理性设计新型高效氧化VOCs催化剂提供理论指导。

催化氧化技术是去除挥发性有机物(VOCs)最有效的途径之一。金属氧化物催化氧化VOCs 一直是环境催化领域的研究热点。而催化剂性能的优劣对催化效率和运行成本有着决定性的影响。因此，如何提高金属氧化物催化剂的活性是推广催化氧化VOCs技术的重要因素。本研究可控制备了N掺杂型化学缺陷碳纳米管，以其为载体，构建了缺陷型碳纳米管负载过渡金属氧化物复合催化剂用于甲苯催化氧化反应。研究发现复合催化剂的吸附氧含量、低温还原性及催化氧化甲苯性能都随着石墨氮含量的增加而增加。本项目拓展制备了五元-七元碳环拓扑缺陷碳纳米管和杂原子掺杂碳氮化物材料，将制备的材料成功用于燃料电池电催化氧还原反应和可见光催化还原六价铀的反应。通过理论与实验结合发现，化学缺陷（杂原子掺杂）和拓扑缺陷都可有效调控基体材料的电子特性，从而调变材料的催化性能，(拓扑缺陷使碳纳米管电子轨道定域化，有利于氧吸附；杂原子掺杂使碳氮化物带隙窄化，增强对可见光的吸收) 这一现象在本研究的催化氧化、电催化及光催化领域催化剂的构建中是通用的。另外，本项目广泛而深入地研究了缺陷在碳纳米管及碳氮材料中的独立作用，将为构建高效催化剂提供一条便捷途径。