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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    

CH<sub>4sub> and N<sub>2sub>O emissions from double-rice cropping system as affected by Chinese milk

Heshui XU,Dengyun LI,Bo ZHU,Kai ZHANG,Yadong YANG,Chen WANG,Ying JIANG,Zhaohai ZENG

《农业科学与工程前沿(英文)》 2017年 第4卷 第1期   页码 59-68 doi: 10.15302/J-FASE-2017137

摘要: Chinese milk vetch (CMV) and rice straw (RS) were incorporated into soil to substitute for synthetic N fertilizers and to maintain soil fertility. However, little is known about the integrated impacts of CMV and RS incorporation on CH and N O emissions in double-rice cropping systems in southern China. A field experiment was conducted to estimate the integrated impacts of CMV and RS incorporation in the early- and late-rice seasons on CH and N O emissions. All treatments received uniform N inputs, 6%–37% of which was replaced by CMV and RS crop residue. CMV and/or RS incorporation produced equivalent or slightly more grain yield, while reducing N O emissions by 3%–43%. However, both CMV and RS incorporation increased CH emissions. Annual CH emissions ranged from 321 to 614 kg·hm from CMV and RS amendment treatments, which were 1.5–2.9 times higher than that from synthetic N. Compared with single synthetic N fertilizer, incorporation of CMV and/or RS increased GWP and yield-scaled GWP by 45%–164% and 45%–153%, respectively. Our results demonstrate CMV and RS amendments replacing N fertilizer, maintained stable yield, mitigated N O emission, but enhanced CH emission. Further study is needed on crop residue management in double-cropping rice systems.

关键词: Chinese milk vetch     CH4     double-rice cropping system     grain yield     N2O     rice straw    

NiCo2O4@quinone-rich N–C core–shell nanowires as composite electrode for electric double layer capacitor

《化学科学与工程前沿(英文)》 2023年 第17卷 第4期   页码 373-386 doi: 10.1007/s11705-022-2223-6

摘要: The bind-free carbon cloth-supported electrodes hold the promises for high-performance electrochemical capacitors with high specific capacitance and good cyclic stability. Considering the close connection between their performance and the amount of carbon material loaded on the electrodes, in this work, NiCo2O4 nanowires were firstly grown on the substrate of active carbon cloth to provide the necessary surface area in the longitudinal direction. Then, the quinone-rich nitrogen-doped carbon shell structure was formed around NiCo2O4 nanowires, and the obtained composite was used as electrode for electric double layer capacitor. The results showed that the composite electrode displayed an area-specific capacitance of 1794 mF∙cm–2 at the current density of 1 mA∙cm–2. The assembled symmetric electric double layer capacitor achieved a high energy density of 6.55 mW∙h∙cm–3 at a power density of 180 mW∙cm–3. The assembled symmetric capacitor exhibited a capacitance retention of 88.96% after 10000 charge/discharge cycles at the current density of 20 mA∙cm–2. These results indicated the potentials in the preparation of the carbon electrode materials with high energy density and good cycling stability.

关键词: carbon cloth     NiCo2O4 nanowires     core−shell structure     quinone-rich     electric double layer capacitor    

N<sub>2sub>O emission from a sequencing batch reactor for biological N and P removal from wastewater

Lei SHEN,Yuntao GUAN,Guangxue WU,Xinmin ZHAN

《环境科学与工程前沿(英文)》 2014年 第8卷 第5期   页码 776-783 doi: 10.1007/s11783-013-0586-0

摘要: Nitrous oxide (N O) is a greenhouse gas that can be released during biological nitrogen removal from wastewater. N O emission from a sequencing batch reactor (SBR) for biological nitrogen and phosphorus removal from wastewater was investigated, and the aims were to examine which process, nitrification or denitrification, would contribute more to N O emission and to study the effects of heterotrophic activities on N O emission during nitrification. The results showed that N O emission was mainly attributed to nitrification rather than to denitrification. N O emission during denitrification mainly occurred with stored organic carbon as the electron donor. During nitrification, N O emission was increased with increasing initial ammonium or nitrite concentrations. The ratio of N O emission to the removed ammonium nitrogen (N O-N/NH -N) was 2.5% in the SBR system with high heterotrophic activities, while this ratio was in the range from 0.14% to 1.06% in batch nitrification experiments with limited heterotrophic activities.

关键词: biological nutrient removal     denitrification     greenhouse gas     nitrification     nitrous oxide    

Effects of Pd doping on N

Mingxin Dong, Jun Wang, Jinxin Zhu, Jianqiang Wang, Wulin Wang, Meiqing Shen

《环境科学与工程前沿(英文)》 2017年 第11卷 第6期 doi: 10.1007/s11783-017-0976-9

摘要: N O is a powerful greenhouse gas and plays an important role in destructing the ozone layer. This present work investigated the effects of Pd doping on N O formation over Pt/BaO/Al O catalyst. Three types of catalysts, Pt/BaO/Al O , Pt/Pd mechanical mixing catalyst (Pt/BaO/Al O +Pd/Al O ) and Pt-Pd co-impregnation catalyst (Pt-Pd/BaO/Al O ) were prepared by incipient wetness impregnation method. These catalysts were first evaluated in NSR activity tests using H /CO as reductants and then carefully characterized by BET, CO chemisorption, CO-DRIFTs and H -TPR techniques. In addition, temperature programmed reactions of NO with H /CO were conducted to obtain further information about N O formation mechanism. Compared with Pt/BaO/Al O , (Pt/BaO/Al O +Pd/Al O ) produced less N O and more NH during NO storage and reduction process, while an opposite trend was found over (Pt-Pd/BaO/Al O +Al O ). Temperature programmed reactions of NO with H /CO results showed that Pd/Al O component in (Pt/BaO/Al O +Pd/Al O ) played an important role in NO reduction to NH , and the formed NH could reduce NO to N leading to a decrease in N O formation. Most of N O formed over (Pt-Pd/BaO/Al O +Al O ) was originated from Pd/BaO/Al O component. H -TPR results indicated Pd-Ba interaction resulted in more difficult-to-reduce PdO species over Pd/BaO/Al O , which inhibits the NO dissociation and thus drives the selectivity to N O in NO reduction.

关键词: NOx storage reduction     Pt/BaO/Al2O3     Pd doping     N2O formation     Optimization    

Physical and chemical processes of wintertime secondary nitrate aerosol formation

Qi YING

《环境科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 348-361 doi: 10.1007/s11783-011-0343-1

摘要: The UCD/CIT model was modified to include a process analysis (PA) scheme for gas and particulate matter (PM) to study the formation of secondary nitrate aerosol during a stagnant wintertime air pollution episode during the California Regional PM /PM Air Quality Study (CRPAQS) where detailed measurements of PM components are available at a few sites. Secondary nitrate is formed in the urban areas from near the ground to a few hundred meters above the surface during the day with a maximum modeled net increase rate of 4 μg·m ·d during the study episode. The secondary nitrate formation rate in rural areas is lower due to lower NO . In the afternoon hours, near-surface temperature can be high enough to evaporate the particulate nitrate. In the nighttime hours, both the gas phase N O reactions with water vapor and the N O heterogeneous reactions with particle-bound water are important for secondary nitrate formation. The N O reactions are most import near the surface to a few hundred meters above surface with a maximum modeled net secondary nitrate increase rate of 1 μg·m ·d and are more significant in the rural areas where the O concentrations are high at night. In general, vertical transport during the day moves the nitrate formed near the surface to higher elevations. During the stagnant days, process analysis indicates that the nitrate concentration in the upper air builds up and leads to a net downward flux of nitrate through vertical diffusion and a rapid increase of surface nitrate concentration.

关键词: secondary nitrate aerosol     N2O5 heterogeneous reaction     process analysis    

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    

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    

固体氧化物电解池共电解H<sub>2sub>O/CO<sub>2sub>研究进展

范慧,宋世栋,韩敏芳

《中国工程科学》 2013年 第15卷 第2期   页码 107-112

摘要: 本文介绍了固体氧化物电解池的结构特点及其用于H2O/CO2的共电解制备H2和CO的工作原理,综述了固体氧化物电解池的组成形式,以及单片电解池和电解池堆用于H2O/CO2共电解反应的国内外研究进展,并阐述了提高固体氧化物电解池共电解效率所亟需解决的问题

关键词: 固体氧化物电解池     H<sub>2sub>O/CO<sub>2sub>共电解     合成气     电解效率     水电解    

含稀释剂的Al-Cr<sub>2sub>O<sub>3sub>体系燃烧合成反应热力学分析与反应模型

张衍诚,潘冶,张传

《中国工程科学》 2004年 第6卷 第6期   页码 63-67

摘要:

对含稀释剂Al203和Cr<sub>2</sub>0<sub>3</sub>的Al-Cr<sub>2</sub>0<sub>3</sub>体系燃烧合成反应进行了热力学计算与分析,讨论了起始反应温度T<sub>0</sub>、稀释剂Al<sub>2</sub>O<sub>3</sub>和Cr<sub>2</sub>O<sub>3</sub>的含量对绝热反应温度7^的影响,并得出T<sub>0</sub>与T<sub>ad</sub>在特定温度段上的近似线性关系以及该关系在指导材料成分设计上的应用;揭示了反应驱动力—&mdash

关键词: 金属陶瓷     燃烧合成     Al-Cr203体系     热力学     反应模型    

ZnFe<sub>2sub>O<sub>4sub> deposited on BiOCl with exposed (001) and (010) facets for photocatalyticreduction of CO<sub>2sub> in cyclohexanol

Guixian Song, Xionggang Wu, Feng Xin, Xiaohong Yin

《化学科学与工程前沿(英文)》 2017年 第11卷 第2期   页码 197-204 doi: 10.1007/s11705-016-1606-y

摘要: ZnFe O -BiOCl composites were prepared by both hydrothermal and direct precipitation processes and the structures and properties of the samples were characterized by various instrumental techniques. The samples were then used as catalysts for the photocatalytic reduction of CO in cyclohexanol under ultraviolet irradiation to give cyclohexanone (CH) and cyclohexyl formate (CF). The photocatalytic CO reduction activities over the hydrothermally prepared ZnFe O -BiOCl composites were higher than those over the directly-precipitated composites. This is because compared to the direct-precipitation sample, the ZnFe O nanoparticles in the hydrothermal sample were smaller and more uniformly distributed on the surface of BiOCl and so more heterojunctions were formed. Higher CF and CH yields were obtained for the pure BiOCl and BiOCl composite samples with more exposed (001) facets than for the samples with more exposed (010) facets. This is due to the higher density of oxygen atoms in the exposed (001) facets, which creates more oxygen vacancies, and thereby improves the separation efficiency of the electron-hole pairs. More importantly, irradiation of the (001) facets with ultraviolet light produces photo-generated electrons which is helpful for the reduction of CO to ·CO . The mechanism for the photocatalytic reduction of CO in cyclohexanol over ZnFe O -BiOCl composites with exposed (001) facets involves electron transfer and carbon radical formation.

关键词: reduction of CO2     cyclohexanol     ZnFe2O4 deposited BiOCl     facet     composite photocatalyst    

Al<sub>2sub>O<sub>3sub>-M<sub>xsub>O<sub>ysub>硬面陶瓷涂层的喷焊制备及性能研究

王飚,王宇栋,李慧玲,张自华

《中国工程科学》 2002年 第4卷 第9期   页码 75-80

摘要:

在碳钢母材上,用氧乙炔焰喷焊镍包铝合金粉末制取预涂层,喷焊50% Al<sub>2sub>O<sub>3sub>+50% Ni的复合粉末制取过渡层,用等离子喷焊Al<sub>2sub>O<sub>3sub> - M<sub>xsub>O<sub>ysub>复合粉末制取最终涂层。

关键词: Al<sub>2sub>O<sub>3sub>-M<sub>xsub>O<sub>ysub>     涂层     等离子     抗腐蚀     抗磨损    

Cu-doped Bi/Bi<sub>2sub>WO<sub>6sub> catalysts for efficient N<sub>2sub> fixation by photocatalysis

《化学科学与工程前沿(英文)》 2023年 第17卷 第10期   页码 1412-1422 doi: 10.1007/s11705-023-2312-1

摘要: In this paper, Cu-doped Bi2WO6 was synthesized via a solvothermal method and applied it in photocatalytic N2 immobilization. Characterization results showed the presence of a small amount of metallic Bi in the photocatalyst, indicating that the synthesized photocatalyst is actually Bi/Cu-Bi2WO6 composite. The doped Cu had a valence state of +2 and most likely substituted the position of Bi3+. The introduced Cu did not affect the metallic Bi content, but mainly influenced the energy band structure of Bi2WO6. The band gap was slightly narrowed, the conduction band was elevated, and the work function was reduced. The reduced work function improved the transfer and separation of charge carriers, which mainly caused the increased photoactivity. The optimized NH3 generation rates of Bi/Cu-Bi2WO6 reached 624 and 243 μmol·L–1·g–1·h–1 under simulated solar and visible light, and these values were approximately 2.8 and 5.9 times higher those of Bi/Bi2WO6, respectively. This research provides a method for improving the photocatalytic N2 fixation and may provide more information on the design and preparation of heteroatom-doped semiconductor photocatalysts for N2-to-NH3 conversion.

关键词: Bi2WO6     Cu doping     work function     photocatalytic N2 fixation     charge separation    

Al<sub>2sub>O<sub>3sub> and CeO<sub>2sub>-promoted MgO sorbents for CO<sub>2sub> capture at moderate

Huimei Yu, Xiaoxing Wang, Zhu Shu, Mamoru Fujii, Chunshan Song

《化学科学与工程前沿(英文)》 2018年 第12卷 第1期   页码 83-93 doi: 10.1007/s11705-017-1691-6

摘要: A series of Al O and CeO modified MgO sorbents was prepared and studied for CO sorption at moderate temperatures. The CO sorption capacity of MgO was enhanced with the addition of either Al O or CeO . Over Al O -MgO sorbents, the best capacity of 24.6 mg-CO /g-sorbent was attained at 100 °C, which was 61% higher than that of MgO (15.3 mg-CO /g-sorbent). The highest capacity of 35.3 mg-CO /g-sorbent was obtained over the CeO -MgO sorbents at the optimal temperature of 200 °C. Combining with the characterization results, we conclude that the promotion effect on CO sorption with the addition of Al O and CeO can be attributed to the increased surface area with reduced MgO crystallite size. Moreover, the addition of CeO increased the basicity of MgO phase, resulting in more increase in the CO capacity than Al O promoter. Both the Al O -MgO and CeO -MgO sorbents exhibited better cyclic stability than MgO over the course of fifteen CO sorption-desorption cycles. Compared to Al O , CeO is more effective for promoting the CO capacity of MgO. To enhance the CO capacity of MgO sorbent, increasing the basicity is more effective than the increase in the surface area.

关键词: CO2 capture     MgO sorbents     Al2O3     CeO2     flue gas    

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    

标题 作者 时间 类型 操作

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

CH<sub>4sub> and N<sub>2sub>O emissions from double-rice cropping system as affected by Chinese milk

Heshui XU,Dengyun LI,Bo ZHU,Kai ZHANG,Yadong YANG,Chen WANG,Ying JIANG,Zhaohai ZENG

期刊论文

NiCo2O4@quinone-rich N–C core–shell nanowires as composite electrode for electric double layer capacitor

期刊论文

N<sub>2sub>O emission from a sequencing batch reactor for biological N and P removal from wastewater

Lei SHEN,Yuntao GUAN,Guangxue WU,Xinmin ZHAN

期刊论文

Effects of Pd doping on N

Mingxin Dong, Jun Wang, Jinxin Zhu, Jianqiang Wang, Wulin Wang, Meiqing Shen

期刊论文

Physical and chemical processes of wintertime secondary nitrate aerosol formation

Qi YING

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

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

期刊论文

固体氧化物电解池共电解H<sub>2sub>O/CO<sub>2sub>研究进展

范慧,宋世栋,韩敏芳

期刊论文

含稀释剂的Al-Cr<sub>2sub>O<sub>3sub>体系燃烧合成反应热力学分析与反应模型

张衍诚,潘冶,张传

期刊论文

ZnFe<sub>2sub>O<sub>4sub> deposited on BiOCl with exposed (001) and (010) facets for photocatalyticreduction of CO<sub>2sub> in cyclohexanol

Guixian Song, Xionggang Wu, Feng Xin, Xiaohong Yin

期刊论文

Al<sub>2sub>O<sub>3sub>-M<sub>xsub>O<sub>ysub>硬面陶瓷涂层的喷焊制备及性能研究

王飚,王宇栋,李慧玲,张自华

期刊论文

Cu-doped Bi/Bi<sub>2sub>WO<sub>6sub> catalysts for efficient N<sub>2sub> fixation by photocatalysis

期刊论文

Al<sub>2sub>O<sub>3sub> and CeO<sub>2sub>-promoted MgO sorbents for CO<sub>2sub> capture at moderate

Huimei Yu, Xiaoxing Wang, Zhu Shu, Mamoru Fujii, Chunshan Song

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