Topological defects strengthened nonradical oxidation performance of biochar catalyzed peroxydisulfate system
Xiaozeng Miao, Xiliang Chen, Wenhao Wu, Daohui Lin, Kun Yang
Biochar ›› 2023, Vol. 5 ›› Issue (1) : 0.
Topological defects strengthened nonradical oxidation performance of biochar catalyzed peroxydisulfate system
| • | Biochar full of topological defects (NBC-T) was developed as excellent PDS catalyst for tetracycline degradation. |
| • | The catalytic activity of NBC-T was found to be positively correlated with the content of topological defects. |
| • | Topological defects with narrow energy gap facilitate electron-transfer thus promoting the generation of holes. |
Nonradical oxidation based on peroxydisulfate (PDS) activation has attracted increasing attention for selective degradation of organic pollutants. Herein, topological defects were introduced into biochar (BC) via removing N atoms in N-doped BC (NBC) in an attempt to improve the nonradical catalytic performance. Compared to the pristine BC and NBC, the introduction of topological defects could achieve up to 36.6- and 8.7-times catalytic activity enhancement, respectively. More importantly, it was found that the catalytic activity was dominated by topological defects, which was verified by the significant positive correlation between the pseudo-first-order rate constants and the content of topological defects. Theoretical calculations suggested that topological defects enhanced the electron-donating ability of BC by reducing the energy gap, which made the electrons transfer to PDS molecules more easily. As a result, holes were generated after the carbon defects lost electrons, and induced a nonradical oxidation process. Benefiting from the merits of nonradical oxidation, the developed BC/PDS system showed superior performance in removing electron-rich contaminants in the presence of inorganic anions and in the actual environments. This study not only provides a potential avenue for designing efficient biochar-based catalysts, but also advances the mechanism understanding of nonradical oxidation process induced by carbon defects.
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