RSC Advances
·
2019
·Vol. 9
·期 5
·2343-2352
·
IF 3.049
Feng Zhao,Shuangde Li,Xiaofeng Wu,Renliang Yue,Weiman Li,Yunfa Chen
CuO–CeO2 nanocatalysts with different amounts of Mn dopping (Mn/Cu molar ratios of 0.5 : 5, 1 : 5 and 1.5 : 5) were synthesized by flame spray pyrolysis (FSP) method and tested in the catalytic oxidation of CO. The physicochemical properties of the synthesised samples were characterized systematically, including using X-ray diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FESEM), Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), oxygen-temperature programmed desorption (O2-TPD), hydrogen-temperature programmed reduction (H2-TPR) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). The results showed that the 1Mn–Cu–Ce sample (Mn/Cu molar ratio of 1 : 5) exhibited superior catalytic activity for CO oxidation, with the temperature of 90% CO oxidation at 131 °C at a high space velocity (SV = 60 000 mL g−1 h−1), which was 56 °C lower than that of the Cu–Ce sample. In addition, the 1Mn–Cu–Ce sample displays excellent stability with prolonged time on CO stream and the resistance to water vapor. The significantly enhanced activity was correlated with strong synergetic effect, leading to fine textual properties, abundant chemically adsorbed oxygen and high lattice oxygen mobility, which further induced more Cu+ species and less formation of carbon intermediates during the CO oxidation process detected by in situ DRIFTS analysis. This work will provide in-depth understanding of the synergetic effect on CO oxidation performances over Mn doped CuO–CeO2 composite catalysts through FSP method.
研究领域:
催化化学
·
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Xinyi Chen,Guangsheng Zou,Yanliang Yuan,Zuwei Xu,Haibo Zhao
The current study investigates a nano-Fe/Ce oxygen carriers (OCs) doped with Ni synthesized by flame spray pyrolysis (FSP) method for the chemical looping dry reforming of methane (CL-DRM). The thermodynamic analysis and reaction simulation of the CL-DRM process with iron-based oxygen carriers are first carried out. The result shows that when reacting with CH 4 , Fe 2 O 3 is reduced to Fe 3 O 4 at first, accompanied by generation of H 2 O and CO 2 , and then to Fe with H 2 and CO production. Fe can be oxidized to Fe 3 O 4 and FeO by CO 2 . Subsequently, based on the reaction patterns obtained from the aforementioned analysis, CL-DRM experiment using Ni-doped Fe/Ce oxygen carriers is conducted in a fixed-bed reactor, and the effects of different Ni doping and reaction conditions on the performance of the oxygen carriers are investigated. The OC with a Ni/Fe molar ratio of 2/98 (2NiFe) achieves over 30% CH 4 conversion and 90% CO selectivity in the partial oxidation step and stable cyclic performance. The FSP process facilitates high dispersion of Ni and formation of NiCe and NiFe alloys, which are stable active sites. Moreover, the transformation of Fe oxides and CeO 2 into CeFeO 3 on the surface of the OC has enhanced lattice oxygen availability and further improved cyclic stability.
研究领域:
化学工程
·
能源科学
✓ 已验证
DOI
高影响因子
CRYSTENGCOMM
·
2022
·Vol. 24
·期 39
·6925-6932
·
IF 3.756
Shuai Hu,Maohui Yuan,Changqing Song,Kai Han,Linxuan Wang,Hanchang Huang,Wenda Cui,Zining Yang,Hongyan Wang
Flame spray pyrolysis (FSP) is a potential strategy to scale-up the fabrication of upconversion nanoparticles (UCNPs) from the laboratory to industrial-scale production. The traditional FSP method involves the addition of 2-ethylhexanoic acid (2-EHA) to the precursors to obtain pure homogeneous ultrafine nanoparticles. However, there is still a lack of investigation into how the physical and optical properties are affected by 2-EHA. Here, for the first time, we report the role of 2-EHA in manipulating the morphology, size, and upconversion (UC) properties of Yb3+/Ho3+ co-doped Y2O3 UCNPs. The Y2O3:Yb3+/Ho3+ UCNPs were synthesized by adjusting the molar ratios of 2-EHA to trivalent rare earth ions (RE3+) in the precursor solution via the FSP method. The influence on the morphology and upconversion luminescence (UCL) properties of the UCNPs by 2-EHA was studied in detail. As the ratio of 2-EHA to RE3+ (2-EHA/RE3+) in the precursors increases from 0 to 3, the synthesized UCNPs initially form a mixture of large hollow particles and homogeneous ultrafine nanoparticles at low ratios and then uniform ultrafine nanoparticles at relatively high ratios. The typical green (550 nm) and red (667 nm) UCL reduce as the 2-EHA/RE3+ ratio increases. Moreover, the effect of 2-EHA on the temperature sensing behavior of the Y2O3:Yb3+/Ho3+ UCNPs was evaluated via the fluorescence intensity ratio (FIR) method based on the non-thermally coupled 5F4/5S2 and 5F5 levels of Ho3+ ions. The highest absolute sensitivity (SA) and relative sensitivity (SR) of 6.259% and 0.483% K−1 at 323 K, respectively, were determined and the sensitivity dependence on the 2-EHA/RE3+ ratio of the UCNPs was comparatively estimated.
研究领域:
材料科学
·
光学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2019
·Vol. 9
·期 3
·256
·
IF 3.444
Feng Zhao,Shuangde Li,Xiaofeng Wu,Renliang Yue,Weiman Li,Xicuo Zha,Yuzhou Deng,Yunfa Chen
CuO-CeO2nanocatalysts with varying CuO contents (1, 5, 9, 14 and 17 wt %) were prepared by one-step flame spray pyrolysis (FSP) and applied to CO oxidation. The influences of CuO content on the as-prepared catalysts were systematically characterized by X-ray diffraction (XRD), N2adsorption-desorption at −196 °C, field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and hydrogen-temperature programmed reduction (H2-TPR). A superior CO oxidation activity was observed for the 14 wt % CuO-CeO2catalyst, with 90% CO conversion at 98 °C at space velocity (60,000 mL × g−1× h−1), which was attributed to abundant surface defects (lattice distortion, Ce3+, and oxygen vacancies) and high reducibility supported by strong synergistic interaction. In addition, the catalyst also displayed excellent stability and resistance to water vapor. Significantly, in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) showed that in the CO catalytic oxidation process, the strong synergistic interaction led readily to dehydroxylation and CO adsorption on Cu+at low temperature. Furthermore, in the feed of water vapor, although there was an adverse effect on the access of CO adsorption, there was also a positive effect on the formation of fewer carbon intermediates. All these results showed the potential of highly active and water vapor-resistive CuO-CeO2catalysts prepared by FSP.Keywords:flame spray pyrolysis;synergistic interaction;CO oxidation;CuO-CeO2nanocatalyst;water resistance;carbon intermediate
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）