Ultrafine Au nanoparticles anchored on Bi2MoO6 with abundant surface oxygen vacancies for efficient oxygen molecule activation

2019 ◽  
Vol 9 (12) ◽  
pp. 3193-3202 ◽  
Author(s):  
Li Guo ◽  
Qiang Zhao ◽  
Huidong Shen ◽  
Xuanxuan Han ◽  
Kailai Zhang ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Oxygen Vacancies ◽  
Au Nanoparticles ◽  
Oxygen Molecule ◽  
Surface Oxygen ◽  
Au Nps

Au NPs were anchored on Bi2MoO6 with rich SOVs to improve O2 activation for photocatalytic degradation of phenol and dye.

scholarly journals Carbon Quantum Dots (CQDs) Decorated Bi2O3-x Hybrid Photocatalysts with Promising NIR-Light-Driven Photodegradation Activity for AO7

Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1031 ◽  
Author(s):  
Tao Xian ◽  
Xiaofeng Sun ◽  
Lijing Di ◽  
Yongjie Zhou ◽  
Jun Ma ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Oxygen Vacancies ◽  
Carbon Quantum Dots ◽  
Light Irradiation ◽  
Light Illumination ◽  
Surface Oxygen ◽  
Simulated Sunlight ◽  
Nir Light

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.

scholarly journals Fabrication and Application of SERS-Active Cellulose Fibers Regenerated from Waste Resource

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2142
Author(s):  
Shengjun Wang ◽  
Jiaqi Guo ◽  
Yibo Ma ◽  
Alan X. Wang ◽  
Xianming Kong ◽  
...  
Keyword(s):  
Au Nanoparticles ◽  
Cellulose Fiber ◽  
Cellulose Fibers ◽  
Regenerated Cellulose ◽  
Sers Substrate ◽  
Au Nps ◽  
Convenient Approach ◽  
Theoretical Simulations ◽  
Difference Time ◽  
Raman Probe

The flexible SERS substrate were prepared base on regenerated cellulose fibers, in which the Au nanoparticles were controllably assembled on fiber through electrostatic interaction. The cellulose fiber was regenerated from waste paper through the dry-jet wet spinning method, an eco-friendly and convenient approach by using ionic liquid. The Au NPs could be controllably distributed on the surface of fiber by adjusting the conditions during the process of assembling. Finite-difference time-domain theoretical simulations verified the intense local electromagnetic fields of plasmonic composites. The flexible SERS fibers show excellent SERS sensitivity and adsorption capability. A typical Raman probe molecule, 4-Mercaptobenzoicacid (4-MBA), was used to verify the SERS cellulose fibers, the sensitivity could achieve to 10−9 M. The flexible SERS fibers were successfully used for identifying dimetridazole (DMZ) from aqueous solution. Furthermore, the flexible SERS fibers were used for detecting DMZ from the surface of fish by simply swabbing process. It is clear that the fabricated plasmonic composite can be applied for the identifying toxins and chemicals.

Adjusting surface oxygen vacancies prompted perovskite as high performance cathode for solid oxide fuel cell

2021 ◽  
Vol 865 ◽  
pp. 158746
Author(s):  
Yongchao Niu ◽  
Xiaoju Yin ◽  
Chengzhi Sun ◽  
Xueqin Song ◽  
Naiqing Zhang
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
High Performance ◽  
Oxygen Vacancies ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Surface Oxygen

scholarly journals Electric Field Assisted Femtosecond Laser Preparation of Au@TiO2 Composites with Controlled Morphology and Crystallinity for Photocatalytic Degradation

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3816
Author(s):  
Xiaojie Li ◽  
Xin Li ◽  
Pei Zuo ◽  
Xiaozhe Chen ◽  
Misheng Liang ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Electric Field ◽  
Photocatalytic Degradation ◽  
Au Nanoparticles ◽  
High Efficiency ◽  
Free Electron Density ◽  
Pulse Delay ◽  
Dye Pollutants ◽  
Amorphous Tio2 ◽  
Laser Liquid

TiO2 is popular in photocatalytic degradation dye pollutants due to its abundance and its stability under photochemical conditions. Au loaded TiO2 can achieve efficient absorption of visible light and deal with the problem of low conversion efficiency for solar energy of TiO2. This work presents a new strategy to prepare Au nanoparticles-loaded TiO2 composites through electric−field−assisted temporally−shaped femtosecond laser liquid-phase ablation of Au3+ and amorphous TiO2. By adjusting the laser pulse delay and electric field parameters, gold nanoparticles with different structures can be obtained, such as nanospheres, nanoclusters, and nanostars (AuNSs). AuNSs can promote the local crystallization of amorphous TiO2 in the preparation process and higher free electron density can also be excited to work together with the mixed crystalline phase, hindering the recombination between carriers and holes to achieve efficient photocatalytic degradation. The methylene blue can be effectively degraded by 86% within 30 min, and much higher than the 10% of Au nanoparticles loaded amorphous TiO2. Moreover, the present study reveals the crystallization process and control methods for preparing nanoparticles by laser liquid ablation, providing a green and effective new method for the preparation of high-efficiency photocatalytic materials.

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