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期刊论文 1373

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Stability of Ni/SiO

Bettina Stolze,Juliane Titus,Stephan A. Schunk,Andrian Milanov,Ekkehard Schwab,Roger Gläser

《化学科学与工程前沿(英文)》 2016年 第10卷 第2期   页码 281-293 doi: 10.1007/s11705-016-1568-0

摘要: Ni/SiO -ZrO catalysts with Ni loadings of 1 to 13 wt-% were prepared, characterized by elemental analysis, X-ray diffraction, N sorption, temperature programmed oxidation, temperature programmed reduction, and tested for their activity and stability in the dry reforming of methane with carbon dioxide at 850 °C, gas hourly space velocity of 6000 and 1800 h and atmospheric pressure. The SiO -ZrO support as obtained through a simple and efficient sol-gel synthesis is highly porous ( = 90 m ·g , = 4.4 nm) with a homogeneously distributed Si-content of 3 wt-%. No loss of Si or formation of monoclinic ZrO , even after steaming at 850 °C for 160 h, was detectable. The catalyst with 5 wt-% Ni loading in its fully reduced state is stable over 15?h on-stream in the dry reforming reaction. If the catalyst was not fully reduced, a reduction during the early stages of dry reforming is accompanied by the deposition of up to 44 mg·g carbon as shown by experiments in a magnetic suspension balance. Rapid coking occurs for increased residence times and times-on-stream starting at 50 h. The Ni loading of 5 wt-% on SiO -ZrO was shown to provide an optimal balance between activity and coking tendency.

关键词: Ni/SiO2-ZrO2     synthesis gas     dry reforming     coking     steaming    

The stabilization effect of Al<sub>2sub>O<sub>3sub> on unconventional Pb/SiO<sub>2sub> catalyst

《化学科学与工程前沿(英文)》 2023年 第17卷 第10期   页码 1423-1429 doi: 10.1007/s11705-023-2315-y

摘要: Similar to Sn, Pb located at the same group (IVA) in the periodic table of elements, can also catalyze propane dehydrogenation to propene, while a fast deactivation can be observed. To enhance the stability, the traditional carrier Al2O3 with a small amount, was introduced into Pb/SiO2 catalyst in this study. It has been proved that Al2O3 can inhibit the reduction of PbO, and weaken the agglomeration and loss of Pb species due to its enhanced interaction with Pb species. As a result, 3Al15Pb/SiO2 catalyst exhibits a much higher stability up to more than 150 h. In addition, a simple schematic diagram of the change of surface species on the catalyst surface after Al2O3 addition was also proposed.

关键词: Pb/SiO2     Al2O3     propane dehydrogenation     propene     stability    

Comparison study on strategies to prepare nanocrystalline Li

Qiang XIAO, Xiaodan TANG, Yefeng LIU, Yijun ZHONG, Weidong ZHU

《化学科学与工程前沿(英文)》 2013年 第7卷 第3期   页码 297-302 doi: 10.1007/s11705-013-1346-1

摘要: A comparison study has been conducted on the strategies for synthesizing nanocrystalline Li ZrO and K-doped Li ZrO absorbents for CO capture at high temperatures, including solid-state and liquid-phase methods, citrate route, and starch-assisted sol-gel method combined with freeze-drying technique. The absorption properties, including uptake rate and absorption capacity, of synthesized absorbents were investigated by thermogravimetric analysis (TGA) at different CO partial pressures. The nanosized Li ZrO crystals synthesized by the citrate route exhibit a faster uptake and a higher, nearly stoichiometric absorption capacity than those synthesized by the solid-state and liquid-phase methods. The doping of K into Li ZrO can significantly improve the uptake rate of CO , especially at low CO partial pressures. For the synthesis of K-doped Li ZrO , the citrate route has poor reproducibility and scalability, whereas the starch-assisted sol-gel method combined with freeze-drying technique is reproducible and easily scaled up, and the thus synthesized absorbents possess excellent CO capture properties.

关键词: CO2 capture     Li2ZrO3     K-doped Li2ZrO3     citrate     starch     freeze-drying technique    

CO<sub>2sub> methanation and co-methanation of CO and CO<sub>2sub> over Mn-promoted Ni/Al<sub>2sub>O<sub>3sub> catalysts

Kechao Zhao,Zhenhua Li,Li Bian

《化学科学与工程前沿(英文)》 2016年 第10卷 第2期   页码 273-280 doi: 10.1007/s11705-016-1563-5

摘要: A series of Mn-promoted 15 wt-% Ni/Al O catalysts were prepared by an incipient wetness impregnation method. The effect of the Mn content on the activity of the Ni/Al O catalysts for CO methanation and the co-methanation of CO and CO in a fixed-bed reactor was investigated. The catalysts were characterized by N physisorption, hydrogen temperature-programmed reduction and desorption, carbon dioxide temperature-programmed desorption, X-ray diffraction and high-resolution transmission electron microscopy. The presence of Mn increased the number of CO adsorption sites and inhibited Ni particle agglomeration due to improved Ni dispersion and weakened interactions between the nickel species and the support. The Mn-promoted 15 wt-% Ni/Al O catalysts had improved CO methanation activity especially at low temperatures (250 to 400 °C). The Mn content was varied from 0.86% to 2.54% and the best CO conversion was achieved with the 1.71Mn-Ni/Al O catalyst. The co-methanation tests on the 1.71Mn-Ni/Al O catalyst indicated that adding Mn markedly enhanced the CO methanation activity especially at low temperatures but it had little influence on the CO methanation performance. CO methanation was more sensitive to the reaction temperature and the space velocity than the CO methanation in the co-methanation process.

关键词: Mn promotion     nickel catalysts     CO2 methanation     co-methanation of CO and CO2    

SiO<sub>2sub> passivation layer grown by liquid phase deposition for silicon solar cell application

Yanlin CHEN,Sihua ZHONG,Miao TAN,Wenzhong SHEN

《能源前沿(英文)》 2017年 第11卷 第1期   页码 52-59 doi: 10.1007/s11708-016-0429-3

摘要: Surface passivation is one of the primary requirements for high efficient silicon solar cells. Though the current existed passivation techniques are effective, expensive equipments are required. In this paper, a comprehensive understanding of the SiO passivation layer grown by liquid phase deposition (LPD) was presented, which was cost-effective and very simple. It was found that the post-annealing process could significantly enhance the passivation effect of the LPD SiO film. Besides, it was revealed that both chemical passivation and field-effect passivation mechanisms played important roles in outstanding passivation effect of the LPD SiO film through analyzing the minority carrier lifetime and the surface recombination velocity of n-type and p-type silicon wafers. Although the deposition parameters had little influence on the passivation effect, they affected the deposition rate. Therefore, appropriate deposition parameters should be carefully chosen based on the compromise of the deposition rate and fabrication cost. By utilizing the LPD SiO film as surface passivation layer, a 19.5%-efficient silicon solar cell on a large-scale wafer (156 mm × 156 mm) was fabricated.

关键词: Si solar cell     passivation     SiO2     liquid phase deposition     carrier lifetime    

Enhanced performance of oxygen vacancies on CO adsorption and activation over different phases of ZrO

《能源前沿(英文)》 2023年 第17卷 第4期   页码 545-554 doi: 10.1007/s11708-023-0867-7

摘要: The effect of oxygen vacancies on the adsorption and activation of CO2 on the surface of different phases of ZrO2 is investigated by density functional theory (DFT) calculations. The calculations show that the oxygen vacancies contribute greatly to both the adsorption and activation of CO2. The adsorption energy of CO2 on the c-ZrO2, t-ZrO2 and, m-ZrO2 surfaces is enhanced to 5, 4, and 3 folds with the help of oxygen vacancies, respectively. Moreover, the energy barrier of CO2 dissociation on the defective surfaces of c-ZrO2, t-ZrO2, and m-ZrO2 is reduced to 1/2, 1/4, and 1/5 of the perfect surface with the assistance of oxygen vacancies. Furthermore, the activation of CO2 on the ZrO2 surface where oxygen vacancies are present, and changes from an endothermic reaction to an exothermic reaction. This finding demonstrates that the presence of oxygen vacancies promotes the activation of CO2 both kinetically and thermodynamically. These results could provide guidance for the high-efficient utilization of CO2 at an atomic scale.

关键词: CO2 activation     oxygen vacancies     ZrO2     different phases    

Preparation of Cu/ZrO

Xinmei LIU, Shaofen BAI, Huidong ZHUANG, Zifeng YAN

《化学科学与工程前沿(英文)》 2012年 第6卷 第1期   页码 47-52 doi: 10.1007/s11705-011-1170-4

摘要: Cu/ZrO catalysts for methanol synthesis from CO /H were respectively prepared by deposition coprecipitation (DP) and solid state reaction (SR) methods. There is an intimate interaction between copper and zirconia, which strongly affects the reduction property and catalytic performance of the catalysts. The stronger the interaction, the lower the reduction temperature and the better the performance of the catalysts. Surface area, pore structure and crystal structure of the catalysts are mainly controlled by preparation methods and alkalinity of synthesis system. The conversion of CO and selectivity of methanol are higher for DP catalysts than for SP catalysts.

关键词: Cu/ZrO2     methanol synthesis     deposition coprecipitation     solid state reaction     CO2/H2    

Synthesis of magnetic Pb/Fe

Hualiang AN, Xinqiang ZHAO, Zhiguang JIA, Changcheng WU, Yanji WANG

《化学科学与工程前沿(英文)》 2009年 第3卷 第2期   页码 215-218 doi: 10.1007/s11705-009-0055-2

摘要: To facilitate the recovery of Pb/SiO catalyst, magnetic Pb/Fe O /SiO samples were prepared separately by emulsification, sol-gel and incipient impregnation methods. The catalyst samples were characterized by means of X-ray diffraction and N adsorption-desorption, and their catalytic activity was investigated in the reaction for synthesizing propylene carbonate from urea and 1,2-propylene glycol. When the gelatin was applied in the preparation of Fe O at 60°C and the pH value was controlled at 4 in the preparation of Fe O /SiO , the Pb/Fe O /SiO sample shows good catalytic activity and magnetism. Under the reaction conditions of a reaction temperature of 180°C, reaction time of 2 h, catalyst percentage of 1.7 wt-% and a molar ratio of urea to PG of 1∶4, the yield of propylene carbonate attained was 87.7%.

关键词: Pb/Fe3O4/SiO2 magnetic particle     urea     1     2-propylene glycol     propylene carbonate    

Rh<sub>2sub>O<sub>3sub>/hexagonal CePO<sub>4sub> nanocatalysts for N<sub>2sub>O decomposition

Huan Liu, Zhen Ma

《化学科学与工程前沿(英文)》 2017年 第11卷 第4期   页码 586-593 doi: 10.1007/s11705-017-1659-6

摘要: Hexagonal CePO nanorods were prepared by a precipitation method and hexagonal CePO nanowires were prepared by hydrothermal synthesis at 150 °C. Rh(NO ) was then used as a precursor for the impregnation of Rh O onto these CePO materials. The Rh O supported on the CePO nanowires was much more active for the catalytic decomposition of N O than the Rh O supported on CePO nanorods. The stability of both catalysts as a function of time on stream was studied and the influence of the co-feed (CO , O , H O or O /H O) on the N O decomposition was also investigated. The samples were characterized by N adsorption-desorption, inductively coupled plasma optical emission spectroscopy, X-ray diffraction, transmission electron microscopy, X-ray photoelectron microscopy, hydrogen temperature-programmed reduction, oxygen temperature-programmed desorption, and CO temperature-programmed desorption in order to correlate the physicochemical and catalytic properties.

关键词: Rh2O3     CePO4     N2O decomposition    

Effect of SiO

Qian WANG, Lei WANG, Hui WANG, Zengxi LI, Xiangping ZHANG, Suojiang ZHANG, Kebin ZHOU

《化学科学与工程前沿(英文)》 2011年 第5卷 第1期   页码 79-88 doi: 10.1007/s11705-010-0550-5

摘要: A series of SAPO-34 molecular sieves with different SiO /Al O ratios have been synthesized for the methanol-to-olefin (MTO) reaction. Their physico-chemical properties are characterized by various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR) and N adsorption-desorption. The results are compared with those of the commercial HZSM-5, which show that the crystallinity and particle diameter of SAPO-34 as well as HZSM-5 increase with SiO /Al O ratio. The variation of BET surface area of SAPO-34 is different from that of HZSM-5 and the sample with SiO /Al O ratio of 0.4 exhibits the highest BET surface area. FT-IR spectra indicate that HZSM-5 has both Br?nsted and Lewis acid sites and Br?nsted acid sites are stronger, whereas SAPO-34 samples are dominated only by Lewis acid sites. When the SiO /Al O ratio increases, propylene and butylenes become the predominant product of the MTO reaction over HZSM-5. In contrast, the main products of this reaction catalyzed by SAPO-34 are ethylene and propylene. According to the product distribution, the reaction mechanism over HZSM-5 catalysts is proposed.

关键词: HZSM-5     SAPO-34     methanol-to-olefin (MTO)     SiO2/Al2O3 ratio    

Inexpensive synthesis of a high-performance Fe

Nadir Abbas, Godlisten N. Shao, Syed M. Imran, Muhammad S. Haider, Hee Taik Kim

《化学科学与工程前沿(英文)》 2016年 第10卷 第3期   页码 405-416 doi: 10.1007/s11705-016-1579-x

摘要: A sol-gel technique has been developed for the synthesis of a magnetite-silica-titania (Fe O -SiO -TiO ) tertiary nanocomposite with improved photocatalytic properties based on the use of inexpensive titania and silica precursors. The exceptional photocatalytic activity of the resulting materials was demonstrated by using them to photocatalyze the degradation of methylene blue solution. The best formulation achieved 98% methylene blue degradation. An interesting feature of the present work was the ability to magnetically separate and reuse the catalyst. The efficiency of the catalyst remained high during two reuses. The synthesized nanomaterials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, ultra-violet-visible spectroscopy, diffuse reflectance spectroscopy, and thermogravimetric analysis. XRD analysis revealed the formation of multicrystalline systems of cubic magnetite and anatase titania crystals. SEM and TEM characterization revealed well-developed and homogeneously dispersed particles of size less than 15 nm. FTIR spectra confirmed the chemical interaction of titania and silica. It was further noticed that the optical properties of the prepared materials were dependent on the relative contents of their constituent metal oxides.

关键词: sol-gel     photocatalysis     magnetic recovery     TiO2     Fe3O4     SiO2    

Theoretical and experimental study on the fluidity performance of hard-to-fluidize carbon nanotubes-based CO2

《化学科学与工程前沿(英文)》 2022年 第16卷 第10期   页码 1460-1475 doi: 10.1007/s11705-022-2159-x

摘要: Carbon nanotubes-based materials have been identified as promising sorbents for efficient CO2 capture in fluidized beds, suffering from insufficient contact with CO2 for the high-level CO2 capture capacity. This study focuses on promoting the fluidizability of hard-to-fluidize pure and synthesized silica-coated amine-functionalized carbon nanotubes. The novel synthesized sorbent presents a superior sorption capacity of about 25 times higher than pure carbon nanotubes during 5 consecutive adsorption/regeneration cycles. The low-cost fluidizable-SiO2 nanoparticles are used as assistant material to improve the fluidity of carbon nanotubes-based sorbents. Results reveal that a minimum amount of 7.5 and 5 wt% SiO2 nanoparticles are required to achieve an agglomerate particulate fluidization behavior for pure and synthesized carbon nanotubes, respectively. Pure carbon nanotubes + 7.5 wt% SiO2 and synthesized carbon nanotubes + 5 wt% SiO2 indicates an agglomerate particulate fluidization characteristic, including the high-level bed expansion ratio, low minimum fluidization velocity (1.5 and 1.6 cm·s–1), high Richardson−Zakin index (5.2 and 5.3 > 5), and low Π value (83.2 and 84.8 < 100, respectively). Chemical modification of carbon nanotubes causes not only enhanced CO 2 uptake capacity but also decreases the required amount of silica additive to reach a homogeneous fluidization behavior for synthesized carbon nanotubes sorbent.

关键词: CO2 capture     CNT-based sorbents     fluidization     SiO2 nanoparticles     fluidized bed reactors    

Preparation of P

Wenjiang LI, Fei XIE, Dongxu HUA, Chunli ZHANG, Chen DAI, Zhenyun YU, Meizhou QI, Shaojun YU

《化学科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 314-317 doi: 10.1007/s11705-010-0573-y

摘要: Silica hollow microspheres containing phosphorous have been prepared by a sol-gel/emulsion method which uses tetraethoxysilane (TEOS) as the precursor for the SiO and phosphoric acid (H PO ) as the precursor for P O . The hollow structure forms an emulsion system which is composed of an oil phase (kerosene, sorbitan monooleate (Span 80)) and an aqueous phase (a viscous sol solution of ethanol, TEOS and H PO ). Some of the phosphorous remains in the final silica shell structure even after calcination at 650°C. The hollow structure of the P O -SiO (silicophosphate) was characterized by X-ray diffraction (XRD), polarized optical microscopy (POM), scanning electron microscopy (SEM), nitrogen adsorption measurement and Fourier transform infrared spectroscopy (FTIR).

关键词: P2O5-SiO2     hollow microspheres     sol-gel/emulsion     phosphoric acid    

Influence of surface modified mixed metal oxide nanoparticles on the electrochemical and mechanical properties of polyurethane matrix

《化学科学与工程前沿(英文)》 2023年 第17卷 第1期   页码 1-14 doi: 10.1007/s11705-022-2176-9

摘要: Newly synthesized functional nanoparticles, 3-amino-1,2,4-triazole (ATA)/SiO2–TiO2 were introduced to the polyurethane (PU) matrix. Electrochemical techniques were used to investigate the barrier properties of the synthesized PU–ATA/SiO2–TiO2 nanocomposite coated steel specimen. In natural seawater, electrochemical impedance spectroscopy experiments indicated outstanding protective behaviour for the PU–ATA/SiO2–TiO2 coated steel. The coating resistance (Rcoat) of PU–ATA/SiO2–TiO2 was determined to be 2956.90 kΩ·cm–2. The Rcoat of the PU–ATA/SiO2–TiO2 nanocomposite coating was found to be over 50% higher than the PU coating. The current measured along the scratched surface of the PU–ATA/SiO2–TiO2 coating was found to be very low (1.65 nA). The enhanced ATA/SiO2–TiO2 nanoparticles inhibited the entry of electrolytes into the coating interface, as revealed by scanning electron microscopy/energy dispersive X-ray spectroscopy and X-ray diffraction analysis of the degradation products. Water contact angle testing validated the hydrophobic nature of the PU–ATA/SiO2–TiO2 coating (θ = 115.4°). When the concentration of ATA/SiO2−TiO2 nanoparticles was 2 wt %, dynamic mechanical analysis revealed better mechanical properties. Therefore, the newly synthesised PU–ATA/SiO2–TiO2 nanocomposite provided excellent barrier and mechanical properties due to the addition of ATA/SiO2–TiO2 nanoparticles to the polyurethane, which inhibited material degradation and aided in the prolongation of the coated steel’s life.

关键词: SiO2/TiO2 nanoparticle     nanocomposite coatings     dynamic mechanical analysis     electrochemical techniques     corrosion     colloids and interfaces    

铝电解用Fe-Ni-Co-Al<sub>2sub>O<sub>3sub>金属陶瓷惰性阳极

邱竹贤,石忠宁,徐君莉

《中国工程科学》 2004年 第6卷 第8期   页码 35-39

摘要:

研制了一种新型铝电解金属陶瓷惰性阳极,阳极基体由Fe-Ni-CoAl<sub>2sub>O<sub>3sub>构成。在石墨坩埚中,960℃温度下,电解质中的氧化铝质量分数为6.0%,摩尔比为2.6;阳极电流密度为1.0 A/cm2,阳极尺寸大小为120 mm×80 mm×mm,石墨阴极尺寸大小为120 mm×40 mm×20 mm,通入的直流电为100~300 A,电解时间各为10 h;实验所得的电解铝产品纯度达到98%以上,杂质主要为Fe,Ni阳极的反电动势为2.45 V,比理论分解电压仅高出0.25 V证明该阳极为惰性阳极,在电解槽中进行的是Al<sub>2sub>O<sub>3sub>的分解反应。

关键词: 铝电解     惰性阳极     反电动势    

标题 作者 时间 类型 操作

Stability of Ni/SiO

Bettina Stolze,Juliane Titus,Stephan A. Schunk,Andrian Milanov,Ekkehard Schwab,Roger Gläser

期刊论文

The stabilization effect of Al<sub>2sub>O<sub>3sub> on unconventional Pb/SiO<sub>2sub> catalyst

期刊论文

Comparison study on strategies to prepare nanocrystalline Li

Qiang XIAO, Xiaodan TANG, Yefeng LIU, Yijun ZHONG, Weidong ZHU

期刊论文

CO<sub>2sub> methanation and co-methanation of CO and CO<sub>2sub> over Mn-promoted Ni/Al<sub>2sub>O<sub>3sub> catalysts

Kechao Zhao,Zhenhua Li,Li Bian

期刊论文

SiO<sub>2sub> passivation layer grown by liquid phase deposition for silicon solar cell application

Yanlin CHEN,Sihua ZHONG,Miao TAN,Wenzhong SHEN

期刊论文

Enhanced performance of oxygen vacancies on CO adsorption and activation over different phases of ZrO

期刊论文

Preparation of Cu/ZrO

Xinmei LIU, Shaofen BAI, Huidong ZHUANG, Zifeng YAN

期刊论文

Synthesis of magnetic Pb/Fe

Hualiang AN, Xinqiang ZHAO, Zhiguang JIA, Changcheng WU, Yanji WANG

期刊论文

Rh<sub>2sub>O<sub>3sub>/hexagonal CePO<sub>4sub> nanocatalysts for N<sub>2sub>O decomposition

Huan Liu, Zhen Ma

期刊论文

Effect of SiO

Qian WANG, Lei WANG, Hui WANG, Zengxi LI, Xiangping ZHANG, Suojiang ZHANG, Kebin ZHOU

期刊论文

Inexpensive synthesis of a high-performance Fe

Nadir Abbas, Godlisten N. Shao, Syed M. Imran, Muhammad S. Haider, Hee Taik Kim

期刊论文

Theoretical and experimental study on the fluidity performance of hard-to-fluidize carbon nanotubes-based CO2

期刊论文

Preparation of P

Wenjiang LI, Fei XIE, Dongxu HUA, Chunli ZHANG, Chen DAI, Zhenyun YU, Meizhou QI, Shaojun YU

期刊论文

Influence of surface modified mixed metal oxide nanoparticles on the electrochemical and mechanical properties of polyurethane matrix

期刊论文

铝电解用Fe-Ni-Co-Al<sub>2sub>O<sub>3sub>金属陶瓷惰性阳极

邱竹贤,石忠宁,徐君莉

期刊论文