两种合成方法制得g-C_3N_4的光催化性能

Effect of two synthetic methods on photocatalytic properties of g-C_3N_4

聚合物半导体材料石墨型氮化碳(g-C3N4)的光催化性能很大程度上受合成条件的影响。为改进这一不利情况,以三聚氰胺为原料,分别在半封闭和氩气保护条件下,通过调节焙烧温度来制备g-C3N4。利用XRD、FT-IR、UV-Vis、DRS对制备样品进行结构表征,利用SPS、降解苯酚来评价样品光催化性能。结果显示:在半封闭体系中制备的g-C3N4随聚合温度的升高,带隙变窄,光谱吸收范围发生红移,光催化活性有所降低,但不明显。在氩气保护体系中制备的g-C3N4随聚合温度的升高带隙明显变窄,光谱吸收范围发生较大的红移,光催化活性显著减弱。实验结果表明:在低温、氩气保护条件下,可以制备出太阳光利用率高、导电性能好、光催化活性好的g-C3N4材料。

This paper is devoted to investigating how to overcome the notorious effect of the synthetic conditions on the photocatalytic performance of Graphite carbon nitride( g-C3N4) —a polymeric semiconductor which has become the hotspot in field of photocatalytic materials. This investigation consists of preparing ecarbon nitride by melamine at different temperatures under the condition of semi-closing and argon shielding,respectively; characterizing its structural properties by XRD,FT-IR,UV-Vis and DRS;and evaluating its photocatalytic performance by SPS and photocatalytic degradation of phenol. The results show that,exposed to the rising synthetic temperature,the g-C3N4's prepared under the semi-closing condition,exhibits a narrowed band gap,a red-shift in spectral absorption range,and no obviously weakened photocatalytic activity; subjected to the rising synthetic temperature,the g-C3N4's prepared under the semi-closing condition,exhibits a significantly narrowed band gap,a greater red-shift in spectral absorption range,and a remarkably weakened photocatalytic activity; and the synthesis of the g-C3N4 with a higher sunlight utilization rate,a higher electrical conductivity and a higher photocatalytic activity is possible with the condition of lower temperature and argon shielding.