Surface oxygen vacancies modified Bi2MoO6 double-layer spheres: Enhanced visible LED light photocatalytic activity for ciprofloxacin degradation

In this work, Bi2O3-x with surface oxygen vacancies was prepared through the NaBH4 reduction of Bi2O3. After that, carbon quantum dots (CQDs) were deposited onto the surface of the Bi2O3-x to obtain a series of the CQDs/Bi2O3-x composites. The HRTEM and XPS characterizations of the CQDs/Bi2O3-x composites suggest that the thickness of surface oxygen vacancies could be adjusted by changing the concentration of NaBH4 solution, and the intimate contact between CQDs and the Bi2O3-x is achieved. Acid orange 7 (AO7) was adopted as the target reactant for investigating the photocatalytic degradation activities of the CQDs/Bi2O3-x composites under simulated sunlight and NIR light irradiation. It is found that the photocatalytic activities of the samples are closely related to the concentration of NaBH4 and content of CQDs. The Bi2O3-x samples exhibit enhanced simulated-sunlight-driven photocatalytic activity compared with Bi2O3. Specifically, the optimal degradation efficiency of AO7 is achieved over the 3R-Bi2O3-x (concentration of NaBH4: 3 mmol/L), which is 1.38 times higher than the degradation AO7 efficiency over Bi2O3. After the decoration of the 3R-Bi2O3-x surface with CQDs, the simulated-sunlight-driven photocatalytic activity of the CQDs/Bi2O3-x composite could be further enhanced. Among the samples, the 15C/3R-Bi2O3-x sample reveals the highest photocatalytic activity, leading to an AO7 degradation percentage of ~97% after 60 min irradiation. Different from Bi2O3 and the 3R-Bi2O3-x, the 15C/3R-Bi2O3-x sample also exhibits near-infrared (NIR)-light-driven photocatalytic degradation activity. In addition, the intrinsic photocatalytic activity of CQDs/Bi2O3-x composite was further confirmed by the degradation of phenol under simulated sunlight and NIR light irradiation. The photocurrent response and electrochemical impedance spectroscopy (EIS) measurements confirm the efficient migration and separation of photogenerated charges in the CQDs/Bi2O3-x samples. The •OH and h+ are proved to be the main reactive species in the simulated sunlight and NIR light photocatalytic processes over the CQDs/Bi2O3-x composites. According to the above experiments, the photocatalytic degradation mechanisms of the CQDs/Bi2O3-x composites under simulated sunlight and NIR light illumination were proposed.

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Single atomic Au induced dramatic promotion of the photocatalytic activity of TiO2 hollow microspheres

Chemical Communications ◽

10.1039/c9cc08578e ◽

2020 ◽

Vol 56 (11) ◽

pp. 1745-1748 ◽

Cited By ~ 13

Author(s):

Zhao Hu ◽

Chao Yang ◽

Kangle Lv ◽

Xiaofang Li ◽

Qin Li ◽

...

Keyword(s):

Photocatalytic Activity ◽

Oxygen Vacancies ◽

Hollow Microspheres ◽

Surface Oxygen

Surface oxygen vacancies (Ov) are used to stabilize single atomic Au on the surfaces of TiO2 hollow microspheres (TiO2-HMSs), sharply improving their photoreactivity towards acetone oxidation.

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Insight into the Contributions of Surface Oxygen Vacancies on the Promoted Photocatalytic Property of Nanoceria

Nanomaterials ◽

10.3390/nano11051168 ◽

2021 ◽

Vol 11 (5) ◽

pp. 1168

Author(s):

Yuanpei Lan ◽

Xuewen Xia ◽

Junqi Li ◽

Xisong Mao ◽

Chaoyi Chen ◽

...

Keyword(s):

Photocatalytic Activity ◽

Oxygen Vacancies ◽

Separation Efficiency ◽

Photocatalytic Property ◽

Pure Hydrogen ◽

Photogenerated Carrier ◽

Surface Oxygen ◽

Photoluminescence Spectra ◽

Electron Hole ◽

Insight Into

Oxygen vacancies (OVs) have critical effects on the photoelectric characterizations and photocatalytic activity of nanoceria, but the contributions of surface OVs on the promoted photocatalytic properties are not clear yet. In this work, we synthesized ceria nanopolyhedron (P-CeO2), ceria nanocube (C-CeO2) and ceria nanorod (R-CeO2), respectively, and annealed them at 600 °C in air, 30%, 60% or pure H2. After annealing, the surface OVs concentration of ceria elevates with the rising of H2 concentration. Photocatalytic activity of annealed ceria is promoted with the increasing of surface OVs, the methylene blue photodegradation ratio with pure hydrogen annealed of P-CeO2, C-CeO2 or R-CeO2 is 93.82%, 85.15% and 90.09%, respectively. Band gap of annealed ceria expands first and then tends to narrow slightly with the rising of surface OVs, while the valence band (VB) and conductive band (CB) of annealed ceria changed slightly. Both of photoluminescence spectra and photocurrent results indicate that the separation efficiency of photoinduced electron-hole pairs is significantly enhanced with the increasing of the surface OVs concentration. The notable weakened recombination of photogenerated carrier is suggested to attribute a momentous contribution on the enhanced photocatalytic activity of ceria which contains surface OVs.

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Photocatalytic activity enhancement of LaPO4via surface oxygen vacancies

RSC Advances ◽

10.1039/c5ra07143g ◽

2015 ◽

Vol 5 (70) ◽

pp. 56711-56716 ◽

Cited By ~ 5

Author(s):

Kai Wang ◽

Wenqing Yao ◽

Fei Teng ◽

Yongfa Zhu

Keyword(s):

Heat Treatment ◽

Photocatalytic Activity ◽

Oxygen Vacancies ◽

Good Stability ◽

Vacuum Heat Treatment ◽

Surface Oxygen ◽

Activity Enhancement

The photocatalytic activity reached a maximum 350 °C with vacuum heat treatment and was almost 1.6 times higher than that of untreated LaPO4. The v-LaPO4 photocatalyst has good stability.

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