| In21st century, the environmental pollution and energy shortages are becoming serious problems with the rapid development of societies, and green or sustainable chemistry has attracted the researchers’ attention, throughout the world as a solution to these problems. Semiconductor photocatalysis has been regarded to be one of the most promising technologies because it can make use of the abundant solar light. Graphitic carbon nitride (g-C3N4) with a lot of advantages such as hydrothermal and chemical stability, visible light response, non-poisonous, cheap raw material and so on, has attracted many attention.The g-C3N4was synthesized by the self-condensation polymerization of melamine at550℃. g-C3N4was treated by hydrothermal method to enlarge its specific surface area. Au and RuO2were chosen to modify g-C3N4. The samples were characterized by BET, XRD, UV-vis, FT-IR, TG, XPS, SEM and TEM. Gaseous acetaldehyde was selected as the organic pollutant to evaluate the photocatalytic activity of the as-prepared samples. The aim is to investigate the effect of specific surface area, different co-catalyst on the structure and photocatalytic activities of the samples.The main research contents and results are as follows:(1) g-C3N4treated with sodium hydroxide solution by hydrothermal method to obtain g-C3N4with high specific surface area. The specific surface area (SBET) of high specific surface area g-C3N4was about45m2/g, while g-C3N4was about10m2/g. high specific surface area g-C3N4showed better photocatalytic activity than g-C3N4. High specific surface area g-C3N4could generate160ppm CO2by decomposition of acetaldehyde, while g-C3N4could generate about80ppm CO2.(2) The Au modified g-C3N4and high specific surface area g-C3N4was synthesized by the deposition-precipitation method. The calcined temperature of the samples played an important role in the photocatalytic activity, the samples calcined at550℃showed the highest photocatalytic activity. However, Au could not work efficiently to improve the photocatalytic activity of the decomposition of acetaldehyde.(3) The RuO2loaded samples were prepared by impregnation method.0.05wt% RuO2-loaded high specific surface area g-C3N4showed the highest photocatalytic activity, which was about6times as unmodified g-C3N4. Enhancement of the activity for acetaldehyde oxidation by an appropriate amount of RuO2loading implies that RuO2with high dispersity or small particle size work as a co-catalyst facilitates efficient oxidation sites, which induced separation of electron-hole pair and. |
