Highly efficient activation of peroxymonosulfate by Co3O4/Bi2WO6 p-n heterojunction composites for the degradation of ciprofloxacin under visible light irradiation

Au and Co3O4 anchored Bi2WO6 with enhanced electron paramagnetic resonance, surface plasmon resonance, nonlinear and magnetic properties

“…This result suggested the OVs were formed in crystals. Similar EPR signals were reported for pure BWO at g = 1.991–2.004 23,33 …”

“…Besides these features, CBWO also had an extra broad absorption peak centered at 700 nm which was attributed to the d-d spin and electron-dipole allowed 4 A 2 (4F) → 4 T 1 (4F) transition of tetrahedral Co 2+ crystal symmetry. 23,35,41 Obvious this broad band overlapped the 5 T 2g → 5 E g transition of Co 3+ ions at the same spectra range. Another 5 E → 5 T 2 transition of Co 3+ ions in Co 3 O 4 around 430 nm was completely covered by the strong absorption edge of CBWO.…”

“…As shown in Figure 6A, the visible light absorption edge of CBWO was not as steep as that of BWO, and the cutoff wavelength also shifted to longer wavelength side. Besides these features, CBWO also had an extra broad absorption peak centered at 700 nm which was attributed to the d–d spin and electron‐dipole allowed 4 A 2 ( 4F ) → 4 T 1 (4 F ) transition of tetrahedral Co 2+ crystal symmetry 23,35,41 . Obvious this broad band overlapped the 5 T 2g → 5 E g transition of Co 3+ ions at the same spectra range.…”

“…18 Even though there were numerous p-n structured materials based on BWO in the past, such as CuBi 2 O 4 , 19 CdS, 6 Bi 2 Sn 2 O 7 , 20 etc. After careful literature review, the very latest BWO-based p-n structures include the pn-type composites with Ta 3 N 5 , 21 CuAlO 2 , 22 Co 3 O 4 , 23 β-Bi 2 O 3 , 24 BioCl, 25 TiO 2 , 26 CuS 27 and even ternary p-n structured Bi 2 S 3 /MoS 2 , 28 Au/Bi 2 WO 6 /BiOBr, 29 and hybrid quaternary polyvinylidene fluoride/CdS/Bi 2 WO 6 /ZnO 30 and CdS/Bi 2 MoO 6 /BiOBr. 31 All of these studies showed enhancement on photocatalytic performance in the visible range, revealing the p-n junction is an efficient approach to improve optical performance of BWO.…”

Synthesis of Bi2MoO6 and Activating Peroxymonosulfate to Enhance Photocatalytic Activity under Visible Light Irradiation

“…[40,41] Recently, PMS was found that it could be activated by photogenerated e − /h + to produce SO 4 •− radicals. [42][43][44] But the degradation efficiency was increased to 98.57% in the Bi 2 MoO 6 /Vis/PMS system in an hour, which meant the degradation efficiency of activating PMS with Bi 2 MoO 6 under visible light irradiation was much better than the Bi 2 MoO 6 only irradiated by visible light. As shown in Figure 7, the degradation efficiency of Bi 2 MoO 6 /Vis/PMS system was also much higher than the other systems.…”