硫元素掺杂石墨相氮化碳光催化剂的制备及其性能研究

Preparation and photocatalytic performance of sulfur-doped graphitic carbon nitride photocatalyst

以三聚氰胺和过硫酸铵为原料,利用简单的一步热聚合法,成功制备出硫元素掺杂的石墨相氮化碳光催化剂(CNS),并以四环素(TC)作为目标降解物,在可见光的照射下,考察所合成的光催化剂的性能.采用XRD、XPS、UV-vis、FT-IR、SEM及PL等一系列表征手段对催化剂的晶相、结构、形貌以及元素组成等进行详细分析.结果表明:S元素掺杂后,体相块状的CN逐渐呈现出分散性良好的二维纳米片状,可提高CN对有机污染物的吸附行为,进而有效地提高其光催化活性.降解实验数据表明,CNS在可见光照射下展现出高效地降解TC的光催化活性,即在120 min后,最优化CNS的光催化降解率可达到80%,其速率常数为0.0125 min^(-1),约为纯相CN的3倍.CNS光催化活性提升的原因主要归功于S元素的引入不仅促使CN在可见光范围内的吸收强度增强,同时也加快CN光生电子的分离效率.

Using melamine and ammonium persulfate as raw materials,the sulfur-doped graphite phase carbon nitride photocatalyst(CNS)was successfully prepared by one-step thermal polymerization.The properties of the synthesized photocatalysts were investigated under visible-light irradiation when the tetracycline(TC)was used as the target pollutant.The crystal phase,structure,morphology and element composition of the catalyst were analyzed by a series of characterization methods such as XRD,XPS,UV-vis,FT-IR,SEM and PL.The results show that bulk CN gradually presents two-dimensional nano-sheets with good dispersion after doping with S element,which can improve the adsorption behavior of CN to degrade organic pollutants and effectively improve its photocatalytic activity.The experimental data showed that CNS exhibited the highest photocatalytic activity in the degradation of TC under visible light irradiation,that is,after 120 min,the optimum photocatalytic degradation rate of CNS was up to 80%,and the rate constant was 0.0125 min^(-1),which was 3 times higher than that of pure CN.The increase of photocatalytic activity of CNS is mainly due to the increase of absorption intensity of CN in visible light range and the separation efficiency of photogenerated electrons in CN.