石墨型C3N4在泡沫陶瓷表面的原位负载及可见光催化空气净化应用

In situ immobilization of g-C_3N_4 on structured ceramic foam and visible light photocatalytic air purification

g-C3N4是一种具有广泛应用前景的无金属可见光催化剂.为了实现g-C3N4在载体表面的有效负载,本研究以二氰二胺为前驱体,通过溶解-再结晶-热处理原位负载工艺,利用g-C3N4和Al2O3之间的独特物理化学作用力,实现了Al2O3泡沫陶瓷上g-C3N4的牢固负载.用X射线衍射、扫描电子显微镜、透射电子显微镜、比表面积测定、紫外可见漫反射光谱和荧光光谱对样品进行表征分析.系统研究了热处理时间对样品微结构和光催化性能的影响.结果表明,当热处理时间为4 h时,负载型g-C3N4具有最优的NO去除率,达57.9%.这可归因于其较大的比表面积和较高的电荷分离效率.本文提供了一种基于光催化剂与载体相互作用的原位负载技术,为g-C3N4在空气净化的实际应用提供了技术支持和理论依据.

g-C3N4 is a metal-free visible light photocatalyst with wide promising application. In this work, an in situ approach of dissolution- recrystallization-thermal-treatment is developed for effective immobilization of g-C3N4 on the support using dicyandiamide as precursor. The immobilized g-C3N4 on A1203 ceramic foam was firm enough owing to the special physicochemical interaction between g-C3N4 and A1203. The g-C3N4 samples were analyzed by techniques. With a systematic investigation on the effects of different pyrolysis time on the microstructure and photocatalytic activity of g-C3N4, it was found that the immobilized g-C3N4 with a pyrolysis time of 4 h exhibited optimal NO removal ratio of 57.9%. The outstanding activity can be ascribed to the increased surface area and porosity and promoted charge separation. This work could provide an in situ immobilization approach based on the interaction between the photocatalyst and support, as well as the technical support and theoretical basis in practical application of g-C3N4 in air purification.