JOURNAL OF CATALYSIS
·
2017
·
IF 6.844
Benxia Li,Baoshan Zhang,Shibin Nie,Liangzhi Shao,Luyang Hu
Exploiting photocatalysts with improved properties for solar-driven chemical reactions is of great significance in developing green chemistry. Here, a series of Au/CeO 2 hybrid nanofibers with different Au loadings have been fabricated by a simple method of electrospinning followed by calcination in air. The particle size and plasmonic absorption of Au nanoparticles (NPs) loaded in the nanofibers were analyzed and found to vary with the dosage of chloroauric acid in the precursor solution. The Au/CeO 2 hybrid nanofibers were used as photocatalysts for selective oxidation of benzyl alcohol to benzaldehyde with O 2 under simulated sunlight and visible light (>420 nm), respectively. The results showed that introducing Au NPs into CeO 2 nanofibers induced a great improvement in photocatalysis. The degree of improvement increased first and then decreased with the increase in Au loading, reaching an optimal level over 0.5 wt.% Au-loaded CeO 2 nanofibers. The photocatalytic reaction presents a very high selectivity of 100% for benzaldehyde, which is important for organic synthesis. The transient photocurrent responses of the Au/CeO 2 catalysts were also tested for corroborative evidence. After detailed discussion of various factors including plasmonic absorption, charge transfer, and surface activity of the photocatalyst, a possible mechanism for the photocatalytic oxidation of benzyl alcohol occurring at the Au–CeO 2 interface was proposed.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2016
·
IF 2.758
Yan Zhang,Ruixia Shi,Ping Yang,Xueling Song,Yuanna Zhu,Qian Ma
The porous CeO 2 nanofibers with diameter of 100–140 nm were successfully synthesized by single-capillary electrospinning of a Ce(NO 3 ) 3 ·6H 2 O/PVP precursor solution, followed by calcination . The preparation parameters, including solution parameters and process parameters, affecting the spinnability and the morphology of nanofibers were investigated and discussed systematically. And the effects of different calcination temperatures on the microstructure CeO 2 nanofibers were also studied. A plausible mechanism was proposed to explain the formation process of the CeO 2 nanofibers. The N 2 adsorption-desorption isotherm analysis showed that the specific surface area and average pore size of the nanofibers were 195.75 g/m 2 and 2.4 nm, respectively. Moreover, as absorbent, the porous CeO 2 nanofibers adsorbed the MO effectively. The adsorption experiment indicated that the adsorption process can be divided into two stages, including quick adsorption and gradual adsorption. And the adsorption capacities were not only determined by the specific surface area, but closely related to the pore size. Finally, the adsorption data were modeled by the pseudo-first-order and pseudo-second-order kinetics equations. The results showed that the pseudo-second order kinetics could best describe the adsorption of MO onto the porous CeO 2 nanofibers.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2024
·
IF 12.7
Dong Wang,Siping Ding,Zhenzhen He,Tonghui Zhang,Xuefen Wang
In this work, a novel Co 3 O 4 @CeO 2 nanofibrous membrane was prepared by the combination of interfacial defect engineering strategy and coaxial electrospinning for unusual levofloxacin degradation. Implanting active Co 3 O 4 into CeO 2 derived from Ce-UiO-66 created more oxygen vacancies and improved the interfacial interaction (electron transfer and specific surface area). In addition, accelerated redox recycling occurred on the catalyst surface because of the cooperation of Co sites and Ce sites. As a result, the optimal Co 3 O 4 @CeO 2 nanocomposite showed an unexpectedly improved degradation efficiency of levofloxacin with a rate constant higher than 6.9 times (CeO 2 ) and 2.6 times (Co 3 O 4 ), superior elimination (>98%) of antibiotic (norfloxacin, tetracycline and doxycycline hydrochloride) and dyes (methylene blue, rhodamine b, methyl orange and crystal violet). Moreover, C-type hollow structure nanofibers with increased reaction area were prepared by coaxial electrospinning to support nanoparticles for consecutive wastewater treatment. The prepared nanofibrous membrane with loading 50 wt% Co 3 O 4 @CeO 2 (PC50 NFMs) exhibited loose structure, resulting in 168.2 ± 12 L m −2 h −1 of permeability driven by gravity, while 164.2 L m −2 of levofloxacin was efficiently treated. Besides, the PC50 NFMs had satisfactory reusability and stability in real water bodies. This work paved a new avenue to control water pollution through the design of membranous catalysts.
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Catalysis
·
2022
·
IF 13.7
Yichao Jin,Sarina Sarina,Hongwei Liu,Wayde Martens,Eric R. Waclawik,Erandi Peiris,Jianfeng Jia,Jing Shang,Liangzhi Kou,Cheng Guo,Huai-Yong Zhu
Production of 2,5-furandicarboxylic acid (FDCA, a platform chemical for the chemical industry in the future) by the selective aerobic oxidation of 5-hydroxymethyl-furfural is a crucial component to enable the FDCA production from sugars. The challenge is to achieve a high FDCA yield at low temperatures. Here, we report a catalyst composed of alloyed nanoparticles (containing 1.5 wt % Ag and 1.5 wt % Pd) supported on CeO2 nanofibers, which achieved an excellent FDCA yield (93%) at 20 °C. Interesting observations include yield deterioration at higher reaction temperatures; water is the source of the oxygen atom(s) added to the oxidized intermediates and product, while O2 molecules adsorbed onto the catalyst scavenge electrons, yielding OH• radicals from OH– ions in the reaction system to drive the oxidation. At 20 °C, we avoid side reactions, but there is no external energy provided for overcoming the activation barriers. The barriers for activating the alcohol groups are significant. We find that the appropriate chemisorption on the catalyst is critical for a high FDCA yield. By tuning the Ag/Pd ratio, we attained the most catalytically active sites, bimetallic surface sites, at the boundaries between Ag and Pd clusters. The chemisorption at these sites is strong enough to cause the selective oxidation of both the aldehyde and alcohol groups in HMF at 20 °C, avoiding side reactions at high temperatures. The knowledge acquired from this study is expected to have implications for other catalytic systems where competitive reactions proceed.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）