球磨干湿环境对原位硫掺杂氮化碳可见光催化性能的影响

Effect of Dry and Wet Environment of Ball Milling on Visible Light Catalytic Performance of Sulfur-Doped Carbon Nitride

以硫脲为原料,通过简单绿色的球磨法提高原位硫掺杂g-C3N4的光催化活性。利用X射线衍射、扫描电子显微镜、元素分析、X射线光电子能谱、紫外-可见漫反射光谱及光致发光光谱等测试方法对其结构和光学特性进行表征。以亚甲基蓝为目标污染物,评价了在不同物料溶剂比下球磨的硫掺杂g-C3N4的可见光催化性能。结果表明,湿式球磨后的硫掺杂g-C3N4光催化剂比表面积增大,反应活性位点的数量增加,带隙宽度也适当增大,氧化还原能力增强。另外,湿式球磨后样品的表面缺陷减少,聚合度增加,促进了光生电子-空穴的有效分离和转移,从而降低其复合率,协同提高了硫掺杂g-C3N4的可见光催化性能。湿式球磨后的样品在可见光照射下对亚甲基蓝的降解速率分别比未球磨的样品和干式球磨后的样品提高了1.5和3.6倍。

The photocatalytic activity of in situ sulfur-doped g-C3N4 was improved by simple and green ball milling using thiourea as raw material.Its structure and optical properties were characterized by X-ray diffraction,scanning electron microscope,elemental analysis,X-ray photoelectron spectroscopy,UV-Vis diffuse reflectance spectroscopy and photoluminescence spectroscopy.The visible light photocatalytic performance of ball milled sulfur-doped g-C3N4 photocatalyst at different solvent ratios was evaluated with methylene blue as the target pollutant.The results show that the specific surface area and the number of reactive sites of the sulfur-doped g-C3N4 photocatalyst after wet ball milling are increased,and the band gap also increased appropriately,resulting in enhanced redox capacity.In addition,the surface defects of the sample after wet ball milling were reduced and the degree of polymerization was increased,which promoted the effective separation and transfer of photogenerated electron-holes.Therefore,the recombination rate can be lowered,and the degradation performance of the sulfur-doped g-C3N4 photocatalyst improved synergistically.The degradation rate of methylene blue in the wet ball milled sample was 1.5 and 3.6 times higher than that of the without ball milled sample and the dry ball milled sample,respectively.