Engineering an oxygen-vacancy-mediated step-scheme charge carrier dynamic coupling WO_3−X/ZnFe₂O₄ heterojunction for robust photo-Fenton-driven levofloxacin detoxification

Abstract

Schematic representation of the photo-Fenton degradation of levofloxacin under solar-light illumination.

0D–2D Fe2O3/Boron-Doped g-C3N4 S-Scheme Exciton Engineering for Photocatalytic H2O2 Production and Photo-Fenton Recalcitrant-Pollutant Detoxification: Kinetics, Influencing Factors, and Mechanism

“…The highest rate constant was obtained for • OH radicals followed by • O 2 – species, indicating their primary role in the degradation process. Moreover, the trapping tests with • OH and • O 2 – radicals further provide an indication toward the formation of an S-scheme-type charge-transfer mechanism instead of staggered type II charge migration between BCN and FQDs of the 3F-BN heterostructure and the reason for this has been well-discussed . However, under an S-scheme charge movement, the photo-excited electrons in the CB of FQDs recombines with the holes in the VB of BCN, resulting in the availability of highly reducing electrons on the CB of BCN and highly oxidizing holes in the VB of FQD, respectively (details discussed below).…”

“…Moreover, when the catalyst amount exceeds the saturation level, the concentration of photon absorption decreases as the extra amount of the catalyst creates a barrier between active sites and irradiated photons, reduces the illuminated area, and finally leads to a decline in photocatalytic activity. 3,36,53 Another important factor that influences the photocatalytic and photo-Fenton process is the pH of the reaction medium, as a change in pH can have a significant impact on the degradation process. In the current study, the photo-Fenton degradation of the pollutant was studied at different pH values.…”

“…Moreover, the trapping tests with • OH and • O 2 − radicals further provide an indication toward the formation of an S-scheme-type charge-transfer mechanism instead of staggered type II charge migration between BCN and FQDs of the 3F-BN heterostructure and the reason for this has been well-discussed. 3 However, under an S-scheme charge movement, the photo-excited electrons in the CB of FQDs recombines with the holes in the VB of BCN, resulting in the availability of highly reducing electrons on the CB of BCN and highly oxidizing holes in the VB of FQD, respectively (details discussed below). In order to further establish the above proposed mechanism, we adopted a • OH radical detection procedure, where non-fluorescence TA was used as a probing reagent.…”

“…Consequently, a number of materials favoring double charge and a Z-scheme band arrangement have been adopted to fabricate BCN-based heterojunctions . Even though e – /h + are well-separated in these mentioned conventional systems, they show certain downsides from a kinetics point of view . Interestingly, in this direction, our group has reported several BCN heterojunction-based systems toward different photocatalytic application with a notable catalytic efficiency. , Additionally, their step-scheme (S-scheme) based charge dynamics give more information regarding separation and transformation of excitons through band bending, internal electric fields, and Coulombic force interpretation .…”

“…In the context of environmental pollution, unsystematic dumping/long-term accumulation of antibiotics, an emerging micro-contaminant, is a serious concern due to their adverse effects on living organisms and health-beneficial healthy bacteria and the spreading of genes of antibiotic-resistant microbes in the ecosystem. 3 The amoxicillin (AMX) drug used for treatment of various bacterial infections has now been traced in aquatic systems and food in the nanograms per liter to micrograms per liter range due to its overuse/improper usage, high stability, and low biodegradability. Moreover, traditional removal techniques are not effective for this micro-pollutant, and hence, a sustainable and effective degradation technique is highly essential.…”