Co3O4负载rGO/g-C3N4臭氧光催化降解2,4-二氯苯氧乙酸活性研究

通过简单的水热法制备了Co₃O₄/rGO/g-C₃N₄催化剂,并在可见光照射下用于光催化臭氧氧化降解2,4-二氯苯氧乙酸(2,4-D)。利用XRD, SEM, TEM, XPS, UV-vis DRS, FT-IR和瞬态光电流对样品进行测试表征。研究表明,Co₃O₄, rGO和g-C₃N₄形成异质结后光生电子-空穴(e--h+)对的分离效率,e-的迁移能力以及光催化臭氧氧化活性都明显提升。此外,0.5Co₃O₄/0.25rGO/GCN对2,4-D具有100%的去除率,并具有最高反应速率(k=0.070 9 min^-1)。经过计算得出光催化臭氧氧化2,4-D的协同因子为3.91,表明光催化和臭氧氧化间具有较好的协同效应。活性组分的捕获实验结果表明h+和·OH是光催化臭氧氧化反应过程中的主要活性物种。此外,经过五次光催化臭氧氧化的循环实验,0.5Co₃O₄/0.25rGO/GCN样品表现处较好的稳定性,本文同时得出光催化臭氧氧化过程的反应机理。

Photocatalytic ozonation of 2,4-dichlorophenoxyacetic acid by Co3O4 loaded rGO/g-C3N4

In this work, Co₃O₄/rGO/g-C₃N₄ catalyst was fabricated by a simple hydrothermal method and employed for visible-light-driven photocatalytic ozonation process towards the degradation of 2,4-dicholorophenoxyacetic acid (2,4-D). The samples were characterized by XRD, SEM, TEM, XPS, UV-vis DRS, FT-IR,and transient photocurrent. Results show that the separation efficiency of photogenerated e--h+ pairs,mobility of e-transfer, and photocatalytic ozonation performance were obviously improved because of the formation of the heterojunction between Co₃O₄, rGO, and g-C₃N₄. Moreover, the removal efficiency for 2,4-D by 0.5Co₃O₄/0.25rGO/GCN was 100% with the highest reaction rate(k=0.070 9 min^-1). The synergy index for photocatalytic ozonation of 2,4-D was calculated to be 3.91, indicating a superior synergistic effect between photocatalysis and ozonation. Results of radical scavenger experiments showed that the reactive species including h+ and ·OH played an important role in the photocatalytic ozonation process. In addition, 0.5Co₃O₄/0.25rGO/GCN samples showed good stability after five cyclesof photocatalytic ozonation process, and the reaction mechanism of photocatalytic ozonation process was obtained.