生物炭
化学
热解
激进的
催化作用
甲基橙
光化学
阴极
羟基自由基
降级(电信)
光催化
兴奋剂
无机化学
化学工程
材料科学
有机化学
工程类
物理化学
电信
光电子学
计算机科学
作者
Ting Zhang,Lu Sun,Xiaohong Sun,Heng Dong,Yu Han,Hongbing Yu
标识
DOI:10.1016/j.jhazmat.2022.129063
摘要
To achieve sustainable metal-free electron-Fenton, N self-doped biochar air-cathode (BCAC) was prepared by pyrolyzing coffee residues. During the pyrolysis process, the endogenous N transformed from edge-doping to graphite-doping. Particularly, N vacancies started to evolve when the peak temperature exceeded 700 °C. A high Tetracycline removal rate of 70.42% was obtained on the BCAC at the current density of 4 mA cm-2. Quenching tests incorporated with ESR spectroscopy were adopted to identify the specific oxidants produced on the cathode. The results showed that •OH (37.36%), •O2- (29.67%) and 1O2 (24.17%) played comparable role in the tetracycline removal, suggesting the coexist of radical and non-radical oxidants in our electro-Fenton system. According to the structure characterization and the DFT calculation, graphitic N was suggested as the critical site for H2O2 generation, and both graphitic N and pyridinic N were electroactive sites for H2O2 activation to •OH. Graphitic N and N vacancies with stronger capabilities in O2 adsorption and electron-trapping were proposed as the electroactive sites for 1O2 and •O2- formation. This work predicts a novel electro-Fenton process with cooperative radical and non-radical degradation on N self-doped carbonaceous catalysts at a mild condition, which is extremely meaningful for boosting sustainable electro-Fenton technology.
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