KOREAN JOURNAL OF CHEMICAL ENGINEERING
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2020
·Vol. 37
·期 4
·623-632
·
IF 2.69
Yan Zhinan,Kang Yong,Li Dan,Liu Yu Chun
Hematite (α-Fe 2 O 3 ) is a promising alternative to the catalysts currently used due to its low cost, fairly good activity and environmentally friendly properties. In this study, α-Fe 2 O 3 /SiO 2 nanocatalysts promoted with cobalt and cerium (Co 3 O 4 -CeO 2 -α-Fe 2 O 3 /SiO 2 ) were prepared via wet co-impregnation method, and the effects of promoters on catalytic performances for SO 2 oxidation at different temperatures, SO 2 concentrations, cycle numbers, catalytic stability as well as catalyst charging were investigated. The results indicated that SO 2 conversion rose with the increasing of catalyst charging and SO 2 concentration. Also, the as-prepared catalyst had the maximum SO 2 conversion at the reaction temperature of 500 °C, excellent catalytic recyclability and activity stability. Its physicochemical and redox properties were characterized by XRD, BET, SEM, FT-IR and XPS. The results of XRD and FT-IR spectra confirmed that the formation of Ce 2 FeO 4 network in the Co-Ce co-doped catalysts proved the promoting effect of cerium on higher valence state of the active ingredient. The N2 adsorption/desorption results evidenced that cerium could increase the proportion of mesoporous, and the XPS spectra indicated that cobalt and cerium in the catalysts could increase the available oxygen (O β /O α ) for the redox reaction. Due to its excellent low onset temperature, fairly good activity and environmentally friendly properties, the as-prepared catalyst of Co 3 O 4 -CeO 2 -α-Fe 2 O 3 /SiO 2 appeared to be more efficient for the SO 2 conversion in a large concentration range.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2021
·
IF 4.641
Wen Ge,Xiaohui Zhang,Xiutao Ge,Kong Liu
Herein, a novel gas-sensing nanocomposite of α-Fe 2 O 3 / x %SiO 2 ( x = 0, 10, 15, 20, 30) was synthesized for the first time by sol-gel. With an increase in SiO 2 concentration to 30 %, the average crystallite size and pore-size distribution of samples exhibited a decreasing trend. The surface area also showed an increasing trend with the introduction of SiO 2 . Gas-sensing measurement results revealed that the α-Fe 2 O 3 /20 %SiO 2 nanocomposite showed the highest response (R a /R g = 50.20) to 500 ppm acetone at its optimal operating temperature of 290 °C, which was about 34 times higher than that of the pure α-Fe 2 O 3 gas sensor. The response/recovery time of the α-Fe 2 O 3 /20 %SiO 2 -based sensor to 500 ppm acetone was 14 s/7 s. The response/recovery time of α-Fe 2 O 3 was 25 s/21 s. After SiO 2 was modified, the response/recovery speed increased. The results demonstrated the potential of α-Fe 2 O 3 /20 %SiO 2 -based gas sensors for sensitive and selective detection of acetone.
研究领域:
材料科学
·
传感器技术
✓ 已验证
DOI
高影响因子
CRYSTENGCOMM
·
2025
·
IF 2.6
Kaiwen Wu,Jichao Shi,Daqing Wang,Honghao Ni,Runping Jia,Yufeng Liu,Lin Lin,Dandan Wu,Shufang Chang,Yaqi Wang,Qing Xin
Magnetic iron oxide is a typical narrow-band gap semiconductor photocatalyst, but its inherent magnetic aggregation effect and high electron–hole recombination rate seriously affect its photocatalytic performance. Here, α-Fe2O3/SiO2 composite aerogels were prepared by combustion technology for the first time. The unique structure of α-Fe2O3/SiO2 composite aerogels with amorphous silica coated with nanocrystalline iron oxide was confirmed. The composite aerogels exhibited a high specific surface area (479 m2 g−1 when calcined at 500 °C), so that they have excellent adsorption properties for organic pollutants (MB, RhB and TC) and Cr(VI). The composite aerogels with a Fe : Si molar ratio of 1 : 2 showed the best visible light photocatalytic properties for MB, RhB and TC. Based on the study of the band gap width, photocurrent density, transient photocurrent response, impedance of photocatalysts, and the unique structure of the composite aerogels, the mechanism of photocatalytic enhancement of composite aerogels was proposed. Finally, the mechanism of the preparation of α-Fe2O3/SiO2 composite aerogels by combustion synthesis was analyzed. It is a potential technology for preparing high performance composite aerogel photocatalysts by high efficiency combustion technology.
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
·
2019
·
IF 6.864
Jiangtao Xu,Songmin Shang,Shouxiang Jiang
Conventionally, the surface-enhanced Raman spectroscopy (SERS) measurement is performed by dispersing noble metal nanoparticles onto the target sample directly or assembling noble metal nanoparticles onto a micro-sized substrate. Despite it is flourishing, this method is not adequate for various samples, mainly limited by either a defined confinement of the test position or the complex extraction process of the target sample on the irregularly shaped surface, besides the costive materials, complex and uncontrollable fabricating processes. Herein, we demonstrate that the α-Fe 2 O 3 thin film is decorated with Ag nanoparticles constructed on SiO 2 fibers as a flexible SERS-active substrate, which yields a functional optical enhancement of the signal at 532 nm laser excitation . It shows a high enhancement factor of 4.71 × 10 5 , ultrahigh sensitivity of 10 −15 M, and excellent signal stability with a relative standard deviation (RSD) of 1.22% and reproducibility with a RSD of 0.258%.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）