Carbon Quantum Dot-Decorated BiOBr/Bi₂WO₆ Photocatalytic Micromotor for Environmental Remediation and DFT Calculation

Abstract

Efficient photocatalysts are crucial for degrading antibiotic pollutants in water and vital for environmental remediation. In this study, an efficient carbon quantum dot (CQD)-modified BiOBr/Bi 2 WO 6 hybrid material was prepared by a mild hydrothermal method. Meanwhile, a visible-light-driven micromotor based on the photocatalyst was developed. The micromotor can achieve self-propelled motion powered by the photocatalytic degradation reaction. It exhibited remarkable photocatalytic activity toward common pollutants in water, such as sulfonamide, quinolone, and tetracycline antibiotics. Among them, 10CQD/BiOBr/Bi 2 WO 6 -4 (10CBBr-4) exhibited the highest photocatalytic activity, which was 2.8 and 5 times higher than those of BiOBr and Bi 2 WO 6 , respectively. The high activity is attributed to the decoration of CQDs, which promoted visible-light absorption. Additional contributions may be due to the specific Z-type electron transport mode and flower-like BiOBr inserted by twodimensional (2D) Bi 2 WO 6 nanosheets, which enriched the active reaction sites, facilitated the adsorption of antibiotic molecules, and promoted the final radical attack. Based on the theoretical calculation of molecular orbitals and the Fukui index, the possible intermediate products, degradation pathways, and photocatalytic mechanism were elucidated. This study suggests that structural engineering based on CQD modification effectively allows the design of selfpropelled microrobots for antibiotic degradation.

Polarization Boosted Solar H2O2 Production over Quantum Dot-Decorated Nanosheets with Rich Oxygen Vacancies

“…Compared with Bi 2 WO 6 and q-BiVO 4 , the Bi 4f peaks exhibit a negative shift for W-0.30V, indicating the different chemical environments of Bi for the samples. The shoulder peaks (165.1–165.4 eV for Bi 4f 5/2 and 159.7/160.2 eV for Bi 4f 7/2 ) occur at higher binding energies for Bi 2 WO 6 and W-0.30V, indicating the appearance of higher electropositive Bi and some Bi atoms bonded with the surface Br atoms. , As shown in Figure d, W 6+ is observed at 35.98 and 38.08 eV in the Bi 2 WO 6 spectrum, assigned to W 4f 7/2 and W 4f 5/2 from [WO 4 ] 2– , respectively . However, the appearance of W 5+ in W-0.30V is observed at binding energies of 35.28 and 37.37 eV, which are assigned to the W 4f 7/2 and W 4f 5/2 orbitals of the W 5+ spectrum. , W 5+ generation is attributed to oxygen vacancies around the W atom formed during the solvothermal process .…”

“…28,39 As shown in Figure 2d, W 6+ is observed at 35.98 and 38.08 eV in the Bi 2 WO 6 spectrum, assigned to W 4f 7/2 and W 4f 5/2 from [WO 4 ] 2− , respectively. 40 However, the appearance of W 5+ in W-0.30V is observed at binding energies of 35.28 and 37.37 eV, which are assigned to the W 4f 7/2 and W 4f 5/2 orbitals of the W 5+ spectrum. 41,42 W 5+ generation is attributed to oxygen vacancies around the W atom formed during the solvothermal process.…”

Optimized silicate nanozymes with atomically incorporated iron and manganese for intratumoral coordination-enhanced once-for-all catalytic therapy

“…ESR measurement using 5,5-dimethyl-1-pyrroline- N -oxide (DMPO) as the trapping agent was used to identify the photodynamic characteristics of FMMSNs, which generate ROS ( 1 O 2 and ˙O 2 − ) under 650 nm light irradiation. 60 As displayed in Fig. S20a and b (ESI†), the characteristic signals of 1 O 2 and ˙O 2 − were observed in the ESR spectra, which gradually enhance with the reaction proceeding.…”

“…ESR measurement using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as the trapping agent was used to identify the photodynamic characteristics of FMMSNs, which generate ROS ( 1 O 2 and O 2 À ) under 650 nm light irradiation. 60 As displayed in Fig. S20a can then be reduced to 1 O 2 by the hole.…”

Correction and new understanding of the reactivity of illuminated tungsten trioxide in the dark: antecedents and consequences of photo-storage electrons triggering Fenton reactions

“…7e, the C (1), C (2), C (4-7), N (12 and 13), O (14) and O ( 16) atoms have a high Fukui (0) index, which indicate that these sites have the theoretically higher radical reactivity. [57][58][59] The C (4), C (6, 7), N (12 and 13) and O (11,(14)(15)(16)(17) have considerable electrophilic reactivity as indicated by their Fukui (−) indexes. [58][59][60][61] The genuine degradation paths of DNBP molecules in the illuminated h-WO 3 $0.46H 2 O/H 2 O 2 system are obtained by GC-MS tests in addition to DFT calculations.…”