研究报告

  • 李一菲,侯诗敏,卫柴汇,吉莉,张越.Ag, Fe, Ce对ZnTi-LDO可见光催化性能的影响及作用机理[J].环境科学学报,2022,42(6):101-110

  • Ag, Fe, Ce对ZnTi-LDO可见光催化性能的影响及作用机理
  • Influences and mechanism of Ag, Fe, Ce on visible light photocatalytic properties of ZnTi-LDO
  • 基金项目:山西省自然科学基金项目(No. 201901D111016);国家自然科学基金项目(No. 42177057)
  • 作者
  • 单位
  • 李一菲
  • 太原科技大学环境科学与工程学院,太原 030024
  • 侯诗敏
  • 太原科技大学环境科学与工程学院,太原 030024
  • 卫柴汇
  • 山西大学化学化工学院,精细化学品教育部工程研究中心,太原 030006
  • 吉莉
  • 太原科技大学环境科学与工程学院,太原 030024
  • 张越
  • 山西大学化学化工学院,精细化学品教育部工程研究中心,太原 030006
  • 摘要:为了解金属及其氧化物对锌钛类水滑石衍生氧化物 (ZnTi-LDO)可见光催化性能的影响, 并获得在可见光下可快速降解染料的LDO光催化剂, 制备了Ag、 Fe、Ce修饰的复合材料 (M-ZnTi-LDO, M=Ag, Ag2O, Fe, Ce). 通过XRD、TEM\HRTEM、 XPS、 BET、 UV-Vis、PL对所合成材料的结构、 形貌、 表面化学状态、 光学性质进行了表征, 评价了上述材料在可见光下对亚甲基蓝 (MB) 的催化降解性能, 通过自由基捕获实验确定了催化降解活性物种, 提出了相关催化机理. 结果表明, Fe、 Ce金属氧化物及金属Ag抑制了材料的可见光催化性能, Ag2O则显著提升了ZnTi-LDO的可见光催化性能. Ag2O-ZnTi-LDO在20 min内即可使MB降解率>98%, 其表观降解速率常数是ZnTi-LDO的7倍. 此外, Ag2O-ZnTi-LDO稳定性良好, 循环5次无催化性能下降. ?O2-是Ag2O-ZnTi-LDO催化降解MB的主要活性物种. Ag2O与ZnTiO3/TiO2形成p-n异质结是其催化性能显著提高的原因.
  • Abstract:To understand the visible light photocatalytic properties of metal and its oxides on zinc-titanium hydrotalcite-derived mixed oxides (ZnTi-LDO), and to obtain an LDO photocatalyst that can rapidly degrade dyes under visible light, the Ag, Fe, Ce modified material (M-ZnTi-LDO, M=Ag, Ag2O, Fe, Ce) were synthesized. The structure, morphology, surface chemical state, and optical properties of the materials were characterized by XRD, TEM\HRTEM, XPS, BET, UV-Vis, PL, and the photocatalysis of the materials on methylene blue (MB) under visible light was evaluated. Active species involved in the photodegradation process of MB were determined with the help of the active species trapping experiment, and a possible mechanism of enhanced photocatalytic activity was proposed. The results show that the visible light photocatalytic performance of ZnTi-LDO was inhibited by Fe, Ce oxides or Ag, but Ag2O-ZnTi-LDO under visible light irradiation exhibit amazingly improved activity in comparison with ZnTi-LDO. For Ag2O-ZnTi-LDO, the degradation percentage of MB up to 98% was observed within only 20 min, and the apparent degradation constant of MB on Ag2O-ZnTi-LDO was ca. 7 times larger than that on ZnTi-LDO. Moreover, Ag2O-ZnTi-LDO exhibits excellent stability without a decline in activity after five cycles. ?O2- is the main active species in the photocatalytic process of MB degradation. The enhanced photocatalytic activity is attributed to the n-p heterostructures between Ag2O and ZnTiO3/TiO2.

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