研究报告

  • 李冬梅,刘小勇,黄毅,廖隽宇,邓紫珞,蒋树贤,冯力.AgI/GO/超薄g-C3N4异质结光催化剂的制备及其可见光催化特性研究[J].环境科学学报,2022,42(6):90-100

  • AgI/GO/超薄g-C3N4异质结光催化剂的制备及其可见光催化特性研究
  • The synthesis of ultrathin heterojunction photocatalyst AgI/GO/g-C3N4 and its photocatalytic performance
  • 基金项目:国家自然科学基金(No.51378129); 广东省自然科学基金(No.2017A030313321); 广东省高教厅-普通高校特色创新类项目(No.2016KTSCX035)
  • 作者
  • 单位
  • 李冬梅
  • 广东工业大学土木与交通工程学院,广州 510006
  • 刘小勇
  • 广东工业大学土木与交通工程学院,广州 510006
  • 黄毅
  • 广东工业大学土木与交通工程学院,广州 510006
  • 廖隽宇
  • 广东广州外国语学校,广州 511400
  • 邓紫珞
  • 华南师范大学附属中学,广州 510630
  • 蒋树贤
  • 广东工业大学土木与交通工程学院,广州 510006
  • 冯力
  • 广东工业大学土木与交通工程学院,广州 510006
  • 摘要:以氧化石墨烯(GO)、超薄g-C3N4 (UCN)、AgNO3和KI为前驱体,首先通过超声法合成GO/超薄g-C3N4(GO/UCN)异质结光催化剂,然后通过化学沉淀法在GO/UCN片层上沉积不同质量分数的AgI纳米颗粒,进一步合成AgI/GO/UCN异质结光催化剂.以罗丹明B(RhB)为目标污染物,测试其可见光催化活性及光催化降解机理.结果表明:① 当AgI质量分数为30%时,AgI/GO/UCN的可见光催化活性最高,在60 min内对RhB的光降解率达到98.42%;② 30%AgI/GO/UCN的最大光吸收边红移至460 nm(UCN为430 nm),禁带宽度由UCN的2.66 eV缩窄至2.53 eV;其瞬态光电流密度提升至2.251 μA·cm-2(而UCN为1.556 μA·cm-2),电化学阻抗谱电弧半径显著减小;③催化剂稳定性良好,重复使用4次对RhB的降解效率仍可达89.61%;④对RhB催化氧化起主要作用的活性物种是·O2-1O2次之;⑤AgI/GO/UCN符合Type-II型异质结,电子聚集在AgI的导带而空穴聚集在UCN的价带中,能有效实现光生电子-空穴对的分离.
  • Abstract:Selecting graphene oxide (GO), ultrathin graphite phase carbon nitride (UCN), AgNO3 and KI as precursors, a new promising heterojunction photocatalyst AgI/GO/UCN was prepared by two steps: the heterojunction photocatalyst GO/UCN was synthesized by ultrasonic method first, then AgI nanoparticles with different mass loading were deposited on GO/UCN by chemical precipitation method. In order to reveal its photocatalytic activity under visible light for pollutant degradation, characterization and photodegradation experiments on RhB were conducted. The results showed that: ①When the mass fraction of AgI was 30%, the AgI/GO/UCN heterojunction was demonstrated the highest photo degradation efficiency for RhB (98.42%); ②For the optimal AgI/GO/UCN, the light absorption wavelength edge was shifted from 430 nm (UCN) to 460 nm and the band gap was narrowed from 2.66 eV (UCN) to 2.53 eV, while the transient photocurrent density was increased from 1.556 μA·cm-2 (UCN) to 2.251 μA·cm-2, with markedly reduced inner resistance expressed by EIS; ③The stability of the AgI/GO/UCN was acceptable and the degradation rate of RhB was still up to 89.61% after four consecutive recycling use; ④·O2- was the dominant active species conducting photocatalysis of RhB, followed by 1O2; ⑤AgI/GO/UCN conformed to Type-II heterojunction. Electrons were clustered in the conduction band of AgI, while the holes were gathered in the valence band of UCN, which can lead to the electron-hole pairs being effectively separated.

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