N缺陷g-C_(3)N_(5)修饰S掺杂苝酰亚胺增强可见光自芬顿苯酚氧化耦合Cr(Ⅵ)还原

Nitrogen-vacancies g-C_(3)N_(5) modified S-doping perylene diimide for the enhanced visible photo self-Fenton reaction for phenol oxidation coupled with Cr(Ⅵ) reduction

通过静电自组装制备有机复合半导体N缺陷g-C_(3)N_(5)(NVs)修饰S掺杂苝酰亚胺(S-PDI)。NVs具有丰富的活性位点,而具有氨基基团的酰胺增强了S-PDI与NVs的分子间作用力。NVs质量分数30%的30%NVs/S-PDI对Cr(Ⅵ)的还原率为79.96%,对苯酚的降解率为74.40%;30%NVs/S-PDI协同氧化苯酚与还原Cr(Ⅵ)过程中,Cr(Ⅵ)的还原率为92.83%,苯酚的降解率为93.89%,即苯酚的氧化降解促进了Cr(Ⅵ)的还原,Cr(Ⅵ)的还原增强了苯酚的氧化降解。NVs/S-PDI充分利用导带的还原性能和价带的氧化性能,实现电子空穴的空间分离,协同强化光催化过程中的氧化半反应和还原半反应,同步提升光催化氧化还原性能。同时,光照产生的电子、H_(2)O_(2)与Cr(Ⅵ)形成一个光自芬顿反应过程,进一步促进了苯酚的氧化降解与Cr(Ⅵ)的还原去除。

Nitrogen-vacancies g-C_(3)N_(5)(NVs) modified S-doping perylene diimide(S-PDI) organic compound semiconductor was prepared by electrostatic self-assembly.The nitrogen vacancies provided rich active sites on the surface of g-C_(3)N_(5).The amide in the preparation of S-PDI enhanced the intermolecular interaction between S-PDI and NVs.The reduction rate of Cr(Ⅵ) over 30%NVs/S-PDI(with NVs mass fraction of 30%) was 79.96%,and the degradation rate of phenol was 74.40%.Furthermore,In the process of synergistic oxidation of phenol and reduction of Cr(Ⅵ) over 30%NVs/S-PDI,the reduction rate of Cr(Ⅵ) was 92.83%,and the degradation rate of phenol was 93.89%.Carboxylic acid and propanol,the products of oxidative degradation of phenol could be used as sacrificial agents of Cr(Ⅵ),which promoted the reduction of Cr(Ⅵ).The reduction of Cr(Ⅵ) enhanced the oxidative degradation of phenol.Accordingly,the carboxylic acid and propanol were finally oxidized to CO_(2)and H_(2)O.Using the reduction performance of the conduction band and the oxidation performance of the valence band,the spatial separation of electrons and holes could be achieved by constructing heterojunction NVs/S-PDI,which could synergistically strengthen the oxidation half-reaction and reduction half-reaction in the photocatalytic process,simultaneously improve the photocatalytic oxidation-reduction performance.At the same time,under the illumination of visible light,H_(2)O_(2)and Cr(Ⅵ) were generated in the phenol aqueous solution.A photo self-Fenton reaction process was formed by the electrons,H_(2)O_(2)and Cr(Ⅵ),which further promoted the oxidative degradation of phenol and the reduction and removal of Cr(Ⅵ).