石墨相氮化碳基光催化剂研究进展

石墨相氮化碳是一种新型的非金属碳氮聚合物,具有优异的光催化性能。本文总结了近年来氮化碳光催化剂的设计与合成,对如何提高其光催化性能的相关工作进行了归纳总结,包括掺杂非金属元素和贵价金属、构建异质结、染料敏化、形貌调控等,并对石墨相氮化碳基光催化剂的后续应用和未来发展进行了展望。     

阴离子对TiO2晶形的影响及光催化性能研究

以SO₄^2-、F^-、Cl^-和PO₄^3-作为阴离子来研究其对水热合成TiO₂(分别记为TiO₂-S、TiO₂-F、TiO₂-Cl和TiO₂-P)晶体的影响,并考察了其光催化性能.SEM显示TiO₂-S、TiO₂-F、TiO₂-Cl和TiO₂-P分别呈粒子、十面体、刺球和不规则块状.XRD图谱表明TiO₂-S和TiO₂-F为锐钛矿晶型,TiO₂-Cl为金红石晶型,而TiO₂-P为锐钛矿、金红石和板钛矿混合晶型,这一结论也被紫外-可见漫反射实验所证实.XPS能谱表明这4种TiO₂纳米材料都受到了各自阴离子掺杂的影响,光催化试验显示:它们的光催化活性顺序为: TiO₂-F>TiO₂-S>TiO₂-Cl>TiO₂-P,这表明锐钛矿的光催化活性要大于金红石和板钛矿,且具有{001}面,掺杂了F的锐钛矿光催化活性更强.     

电化学法合成BiOCl薄膜及其光催化活性研究

以金属Bi板为阳极,石墨为阴极,NaClO为电解液,在室温下用电化学法一步合成了BiOCl薄膜光催化剂.采用X射线衍射(XRD)、紫外可见漫反射(DRS)、扫描电镜(SEM)、透射电子显微镜(TEM)对其组成、光学特性和形貌进行表征.以500 W氙灯为光源,磺胺甲恶唑为目标降解物,研究了NaClO用量、电解电流大小、EDTA添加量以及电解溶液初始pH不同制备条件下对所得BiOCl薄膜催化活性的影响.结果表明,合成的BiOCl-0薄膜为组分单一、均匀的片状结构,在模拟太阳光下照射150m in,磺胺甲恶唑的降解率达89.8;,而且该薄膜具有较好的光催化稳定性.     

水体中常见阴、阳离子对Fe（Ⅲ）/UV催化降解罗丹明B的影响

为研究溶解氧和外加阴、阳离子对Fe（Ⅲ）/UV催化降解罗丹明B的影响,在间歇式光化学反应器中进行了系列对照试验,用一级动力方程拟合得到了各种条件下罗丹明B的降解速率常数k.结果表明,溶液中氧含量增加能加速罗丹明B的Fe（Ⅲ）/UV催化降解,k提高程度与溶液pH值有关;阴离子草酸根、柠檬酸根、硝酸根能促进罗丹明B的Fe（Ⅲ）/UV催化降解,最佳草酸根和柠檬酸根用量分别为Fe（Ⅲ）物质量浓度的3和4倍,HCO3^-、Cl^-、腐植酸会不同程度地抑制罗丹明B的Fe（Ⅲ）/UV催化降解;阳离子钾、钠、钙、镁均可促进罗丹明B的Fe（Ⅲ）/UV催化降解,但它们对降解速率的提高程度各不相同,并与其溶液的质量浓度有关.上述结果提示Fe（Ⅲ）/UV用于处理含罗丹明B的实际废水时应注意水中其他共存离子对催化降解过程的影响.     

Synthesis of the Dy: SrMoO4 with High Photocatalytic Activity under Visible Light Irradiation

Dysprosium (Dy)‐doping SrMoO₄ (with different molar ratio of Dy/Sr = 0/100, 10/100, 15/100 and 20/100) have been synthesized by high temperature thermal decomposition of metal–organic salt in organic solvent with a high boiling point. Their structures, morphology, and optical properties were characterized by X‐ray diffraction (XRD), high‐resolution tuning electron microscopy ((HR)TEM), X‐ray photo‐electron spectroscopy (XPS), and UV–vis diffuse reflectance spectroscopy (UV–vis DRS). Using this method, the pure phase, nano‐size, and low band gap of SrMoO₄ sample are obtained. The results shows that the size of as‐synthesized SrMoO₄ nanoparticles was about 200 nm. The band gap of Dy‐doped SrMoO₄ ranges from 3.76–3.90 eV, and decreases with increasing Dy concentration. The photocatalytic performance of as‐syntheszied products were determined from the degradation of methylene blue (MB) by UV–vis light irradiation. The 15 mol%Dy‐doped SrMoO₄ sample shows the best performance for photocatalytic degradation of methyl blue of nearly 100% in 120 min under visible irradiation, which is higher than most of those reported before. The present work is meaningful for revealing the underlying mechanism in photocatalyst and improving the photocatalytic performance.