二元碱金属共掺杂石墨相氮化碳的制备及光催化性能评价

Preparation of Alkali Metals Co-doped Graphitic Carbon Nitride by Molten Salt Method and Photocatalytic Performance

中文关键词: 石墨相氮化碳 碱金属 光催化 可见光

英文关键词: g-C₃N₄, alkali metal, photocatalysis, visible light

中文摘要:

      以三聚氰胺为母体、以双组分碱金属为熔盐制备了钾-钠共掺杂石墨型氮化碳(g-C₃N₄)光催化剂,并用X射线衍射光谱(XRD)、紫外可见光谱(UV-Vis)、N₂吸附脱附、X光电子能谱(XPS)、荧光光谱(PL)等分析手段对产物进行了表征。结果表明,通过改变碱金属熔盐量,能将氮化碳价带(VB)能级从+1.55 V调控到+2.27 V、导带(CB)能级从-1.10 V调控到-0.27 V,同时碱金属的引入抑制了氮化碳晶粒的生长,降低了光生电子-空穴对的复合概率,提高了氮化碳的比表面积以及对可见光的吸收。以罗丹明B(RhB)为目标物研究了系列氮化碳在可见光驱动下的催化能力,实验结果表明,二元碱金属的掺入大大提高了催化剂降解和矿化罗丹明B的能力,并表现出良好的稳定性。

英文摘要:

      Alkali metals co-doped graphitic carbon nitride (g-C₃N₄) was prepared using melamine as precursor, KCl and NaCl as molten salts, and characterized by X-ray diffraction (XRD), N₂ adsorption, UV-vis spectroscopy, X-ray photoelectron spectroscopy (XPS), and Photoluminescence (PL). By controlling the weight ratio of eutectic salts to melamine, the VB and CB potentials of prepared g-C₃N₄ could be tuned from +1.55 V and -1.10 V to +2.27 V and -0.27 V, respectively. Besides, the ions embedding inhibited the crystal growth, enhanced the separation rate of photo-generated electrons and holes, and enlarged the surface area. The catalytic abilities of products were investigated by photodegradation and mineralization of Rhodamine (RhB) under visibe light. The results showed that photocatalytic activity and stability of prepared catalysts were significantly improved after alkali metals doping.