Carbon nitride–based cuprous catalysts induced nonradical-led oxidation by peroxydisulfate: Role of cuprous and dissolved oxygen

Selective Degradation of Electron-Rich Organic Pollutants Induced by CuO@Biochar: The Key Role of Outer-Sphere Interaction and Singlet Oxygen

“…Potentially, there were three pathways accounting for the 1 O 2 generation in the e-CuO@BC/PDS system: (i) considering the standard redox potential of O 2 /O 2 •– , O 2 •– / 1 O 2 , Cu­(II)/Cu­(I), and S 2 O 8 2– /SO 4 2– of −0.33, −0.34, 0.17, and 2.07 V vs RHE in aqueous solution, respectively, , it is thermodynamically possible to generate 1 O 2 continually based on O 2 •– mediating Cu­(I)/Cu­(II) and dissolved oxygen [eqs –]; (ii) electrons were transferred from the CuO surface to reduce O 2 to O 2 •– with the assistance of the abundant oxygen vacancies in the CuO lattice, resulting in the formation of 1 O 2 ; and (iii) electron transfer was facilitated by the abundant oxygen-containing functional groups of BC, contributing to the generation of 1 O 2 [eqs and ]. …”

“…Based on organic intermediates analyzed by GC–MS shown in Figure S12, the 2,4-DCP degradation pathways were put forward. As presented in Figure a, with a series of electron abstraction reactions (achieved by the attack of 1 O 2 on hydroxyl groups via electron transfer owing to the high electron density of 1 O 2 ), 2,4-DCP was first oxidized into phenoxy radicals and phenoxy cations. It had been proposed that phenoxy radicals can be reduced to hydroquinone by electron transfer .…”

Mixed Nanocomposites of Cu2O and Mn3O4 to Activate Peroxydisulfate for Efficient Degradation of Tetracycline via Cu(III) Species

“…Being different from the Co-, Mn-, and Fe-based catalysts, the reactive species of Cu-based catalysts in different studies are more diverse, including • OH, SO 4 •– , O 2 •– , 1 O 2 , and Cu­(III). ,, Scavengers, such as MeOH, BQ, β-carotene, and NaN 3 , were used to identify the reactive species. As presented in Figure b, there was negligible suppression of TC removal after the addition of BQ, β-carotene, or NaN 3 , suggesting a minor contribution of O 2 •– and 1 O 2 .…”

“…Until now, there are very few reports related to the Cu­(I)-based catalyst/PDS system. One of the few examples comes from Wang and co-workers, who prepared carbon nitride-based Cu­(I) catalysts for the degradation of tetrabromobisphenol A, with the Cu­(I)–N bonds as the active sites . Liu et al synthesized a Cu 0 –Cu 2 O@CNT catalyst that could in situ generate Cu­(I) to activate PDS for 2,4-dichlorophenol degradation .…”

“…One of the few examples comes from Wang and co-workers, who prepared carbon nitridebased Cu(I) catalysts for the degradation of tetrabromobisphenol A, with the Cu(I)−N bonds as the active sites. 21 Liu et al synthesized a Cu 0 −Cu 2 O@CNT catalyst that could in situ generate Cu(I) to activate PDS for 2,4-dichlorophenol degradation. 22 Cu 2 O is the most direct source of Cu(I); however, the large particle size, low catalytic performance, and instability of pure Cu 2 O make it unacceptable for PDS activation.…”