可见光增强室温催化分解甲醛复合材料的液相合成及机理

The design and preparation of micro-nano composite catalysts with high-performance for formaldehyde (HCHO) removal at room temperature is one of the hot research topics in indoor air purification. So far, the composite materials for catalytic oxidation of HCHO at room temperature could be easily deactivated by the accumulated intermediates. Moreover, the high price due to the relatively high content of noble metal used (~ 1 wt%) retards the wide application of the current composite catalysts. On the basis of our previous investigations of adsorption-catalytic oxidation materials for room-temperature removal of HCHO, this project will focus on the liquid-phase synthesis and performance of the visible-light enhanced metal oxide semiconductor-based nanocomposites with much low amount of noble metal (< 0.1 wt%) for catalytic oxidation of HCHO at room temperature. The as-prepared catalysts themselves have excellent activity toward HCHO removal at room temperature. Furthermore, the generated reactive oxygen species produced at the semiconductor support under visible-light illumination could quickly decompose the accumulated intermediates, and thus enhance the anti-poisoning performance and catalytic activity of the catalysts. The influence of preparation parameters on the catalytic performance of the catalysts will be investigated and their tuning ways will be summarized. The synergetic functions among visible-light illumination, metal oxide semiconductor-based support and noble metal will be discussed, and the mechanism of the catalytic oxidation of HCHO at room temperature with and without visible-light illumination will be explored. This work will enrich the catalytic materials of room-temperature catalysts for HCHO removal and the mechanism of HCHO decomposition at room temperature, which will provide new insights into the fabrication of novel materials and the development of high-efficient method for HCHO removal at room temperature.

高效室温催化氧化甲醛材料的设计和制备是室内空气净化领域的研究热点之一。针对甲醛去除过程中累积的中间产物占据了催化剂上的活性位而使其较快失活，及当前室温去除甲醛催化剂使用了约1wt%贵金属而存在价格高等问题，本项目拟采用简单的液相合成法制备可见光（日光灯）增强的含有丰富表面羟基的半导体基负载低含量贵金属（<0.1 wt%）复合催化剂。该材料本身具有优异的室温催化氧化甲醛活性；在可见光光照下，半导体基载体上产生的活性氧物种能加快吸附在催化剂表面上的中间产物的氧化，从而延缓催化剂中毒和增强其催化活性。探讨液相合成中反应条件对催化剂性能的影响规律；揭示可见光、半导体基载体与贵金属纳米颗粒间的协同作用机制，实现热催化和光催化过程的协同调控；阐释可见光增强室温催化分解甲醛机理。本研究可以丰富室温催化氧化甲醛复合催化剂的材料体系及甲醛催化氧化机理，为高活性、强稳定性的室温催化分解甲醛材料的制备提供思路。

甲醛是典型的室内空气污染物，严重地危害人体健康。目前，最具有应用前景的室温分解去除甲醛方法中的高效催化剂主要是负载贵金属型（约1 wt%）复合催化剂。针对该种催化剂价格相对昂贵和在使用中贵金属纳米颗粒易团聚而失活等缺点，本项目采用简单的液相合成法设计和制备了几种低贵金属含量和可以利用室内可见光增强去除甲醛活性的不含贵金属的催化剂，研究了它们在室温下催化去除甲醛的活性和甲醛去除性能增强的可能机理。项目主要研究内容包括：（1）低含量贵金属复合催化剂例如Pt/NiMoO4（0.8 wt% Pt）、Pt/Mn(Co)CO3/MnCo2O4（0.4 wt% Pt）和Pt/g-C3N4@CeO2（0.025 wt% Pt）等的液相法制备；（2）低含量贵金属复合催化剂催化去除甲醛性能和组份间的协同作用机理；（3）无贵金属负载的室温催化去除甲醛材料例如g-C3N4@CeO2，CeO2和g-C3N4等的液相制备及其表面化学性质的调控；（4）非贵金属催化剂室温去除甲醛性能及室内荧光灯照射增强其去除甲醛活性机制。探讨了液相合成中的重要条件对催化剂性能的影响规律；揭示了功能性载体与贵金属纳米颗粒间的协同作用机制；阐释了室内荧光灯光照增强半导体催化剂室温催化分解甲醛的可能机理。本项目的研究成果丰富了室温氧化去除甲醛的催化剂体系及甲醛催化氧化机理，为高活性且能充分利用室内能源（如室内光能）的低温催化分解甲醛和其它挥发性有机污染物的催化剂体系的设计和制备提供思路。