石墨型C₃N₄在泡沫陶瓷表面的原位負載及可見光催化空氣淨化應用

g-C₃N₄是一種具有廣泛應用前景的無金屬可見光催化劑。為了實現g-C₃N₄在載體表面的有效負載，本研究以二氰二胺為前驅體，通過溶解-再結晶-熱處理原位負載工藝，利用g-C₃N₄和Al₂O₃之間的獨特物理化學作用力，實現了Al₂O₃泡沫陶瓷上g-C₃N₄的牢固負載。用X射線衍射、掃描電子顯微鏡、透射電子顯微鏡、比表面積測定、紫外可見漫反射光譜和螢光光譜對樣品進行表徵分析。系統研究了熱處理時間對樣品微結構和光催化性能的影響。結果表明，當熱處理時間為4 h時，負載型g-C₃N₄具有最優的NO去除率，達57.9%。這可歸因於其較大的比表面積和較高的電荷分離效率。本文提供了一種基於光催化劑與載體相互作用的原位負載技術，為g-C₃N₄在空氣淨化的實際應用提供了技術支援和理論依據。

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 Al₂O₃ ceramic foam was firm enough owing to the special physicochemical interaction between g-C₃N₄ and Al₂O₃. 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. Copyright © 2015 《中國科學》雜誌社.