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Effective regeneration of thermally deactivated commercial V-W-Ti catalysts

Xuesong SHANG, Jianrong LI, Xiaowei YU, Jinsheng CHEN, Chi HE

《化学科学与工程前沿(英文)》 2012年 第6卷 第1期   页码 38-46 doi: 10.1007/s11705-011-1167-z

摘要: An effective method for the regeneration of thermally deactivated commercial monolith SCR catalysts was investigated. Two types of regenerated solutions, namely NH Cl (1 mol/L) and dilute H SO (0.5 mol/L), were employed to treat the used catalyst. The effects of temperature and the regeneration process on the structural and textural properties of the catalysts were determined by X-ray diffraction, scanning electron microscopy, N adsorption/desorption, elemental analysis and Fourier transform infrared spectroscopy. The results suggest that the anatase phase of the used catalyst is maintained after exposure to high temperatures. Some of the catalytic activity was restored after regeneration. The catalyst regenerated by aqueous NH Cl had a higher activity than that of the catalyst treated by dilute H SO . The main reason is that the NH generated from the decomposition of NH Cl at high temperatures can be adsorbed onto the catalyst which promotes the reaction. The aggregated V O were partially re-dispersed during the regeneration process, and the intrinsic oxidation of ammonia with high concentrations of O is a factor that suppresses the catalytic activity.

关键词: V2O5-WO3/TiO2 catalysts     thermal deactivation     regeneration     NH4Cl     dilute H2SO4 solution    

Chemical deactivation of V

Xiaodong WU, Wenchao YU, Zhichun SI, Duan WENG

《环境科学与工程前沿(英文)》 2013年 第7卷 第3期   页码 420-427 doi: 10.1007/s11783-013-0489-0

摘要: V O -WO /TiO catalyst was poisoned by impregnation with NH Cl, KOH and KCl solution, respectively. The catalysts were characterized by X-ray diffraction (XRD), inductively coupled plasma (ICP), N physisorption, Raman, UV-vis, NH adsorption, temperature-programmed reduction of hydrogen (H -TPR), temperature-programmed oxidation of ammonia (NH -TPO) and selective catalytic reduction of NO with ammonia (NH -SCR). The deactivation effects of poisoning agents follow the sequence of KCl>KOH>>NH Cl. The addition of ammonia chloride enlarges the pore size of the titania support, and promotes the formation of highly dispersed V=O vanadyl which improves the oxidation of ammonia and the high-temperature SCR activity. K ions are suggested to interact with vanadium and tungsten species chemically, resulting in a poor redox property of catalyst. More importantly, potassium can reduce the Br?nsted acidity of catalysts and decrease the stability of Br?nsted acid sites significantly. The more severe deactivation of the KCl-treated catalyst can be mainly ascribed to the higher amount of potassium resided on catalyst.

关键词: V2O5-WO3/TiO2     potassium chloride     poisoning     reducibility     acid sites    

Characterization and performance of V

Caiting LI, Qun LI, Pei LU, Huafei CUI, Guangming ZENG

《环境科学与工程前沿(英文)》 2012年 第6卷 第2期   页码 156-161 doi: 10.1007/s11783-010-0295-x

摘要: A series of CeO supported V O catalysts with various loadings were prepared with different calcination temperatures by the incipient impregnation. The catalysts were evaluated for low temperature selective catalytic reduction (SCR) of NO with ammonia (NH ). The effects of O and SO on catalytic activity were also studied. The catalysts were characterized by specific surface areas (S ) and X–ray diffraction (XRD) methods. The experimental results showed that NO conversion changed significantly with the different V O loading and calcination temperature. With the V O loading increasing from 0 to 10 wt%, NO conversion increased significantly, but decreased at higher loading. The optimum calcination temperature was 400°C. The best catalyst yielded above 80% NO conversion in the reaction temperature range of 160°C–300°C. The formation of CeVO on the surface of catalysts caused the decrease of redox ability.

关键词: V2O5/CeO2 catalysts     NH3-SCR (selective catalytic reduction)     the incipient impregnation     low temperatures    

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    

On the monolayer dispersion behavior of Co<sub>3sub>O<sub>4sub> on HZSM-5 support: designing applicablecatalysts for selective catalytic reduction of nitrogen oxides by ammonia

《化学科学与工程前沿(英文)》 2023年 第17卷 第11期   页码 1741-1754 doi: 10.1007/s11705-023-2332-x

摘要: Based on monolayer dispersion theory, Co3O4/ZSM-5 catalysts with different loadings have been prepared for selective catalytic reduction of nitrogen oxides by ammonia. Co3O4 can spontaneously disperse on HZSM-5 support with a monolayer dispersion threshold of 0.061 mmol 100 m–2, equaling to a weight percentage around 4.5%. It has been revealed that the quantities of surface active oxygen (O2) and acid sites are crucial for the reaction, which can adsorb and activate NOx and NH3 reactants effectively. Below the monolayer dispersion threshold, Co3O4 is finely dispersed as sub-monolayers or monolayers and in an amorphous state, which is favorable to generate the two kinds of active sites, hence promoting the performance of ammonia selective catalytic reduction of nitrogen oxide. However, the formation of crystalline Co3O4 above the capacity is harmful to the reaction performance. 4% Co3O4/ZSM-5, the catalyst close to the monolayer dispersion capacity, possesses the most abundant active O2 species and acidic sites, thereby demonstrating the best reaction performance in all the samples. It is proposed the optimal Co3O4/ZSM-5 catalyst can be prepared by loading the capacity amount of Co3O4 onto HZSM-5 support.

关键词: Co3O4/ZSM-5     NOx-SCR by NH3     monolayer dispersion threshold effect     surface acid sites     surface active O2 anions    

Simultaneous removal of NO and chlorobenzene on VO/TiO granular catalyst: Kinetic study and performance

《环境科学与工程前沿(英文)》 2021年 第15卷 第4期 doi: 10.1007/s11783-020-1363-5

摘要:

• A V2O5/TiO2 granular catalyst for simultaneous removal of NO and chlorobenzene.

关键词: NOx     Chlorobenzene     Simultaneous removal     Kinetic study     Performance prediction     V2O5/TiO2     Graphical abstract    

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    

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    

Interfacial charge transfer and photocatalytic activity in a reverse designed BiO/TiO core-shell

《能源前沿(英文)》 2021年 第15卷 第3期   页码 732-743 doi: 10.1007/s11708-021-0772-x

摘要: In this study, the electronic and photocatalytic properties of core-shell heterojunctions photocatalysts with reversible configuration of TiO2 and Bi2O3 layers were studied. The core-shell nanostructure, obtained by efficient control of the sol-gel polymerization and impregnation method of variable precursors of semiconductors, makes it possible to study selectively the role of the interfacial charge transfer in each configuration. The morphological, optical, and chemical composition of the core-shell nanostructures were characterized by high-resolution transmission electron microscopy, UV-visible spectroscopy and X-ray photoelectron spectroscopy. The results show the formation of homogenous TiO2 anatase and Bi2O3 layers with a thickness of around 10 and 8 nm, respectively. The interfacial charge carrier dynamic was tracked using time resolved microwave conductivity and transition photocurrent density. The charge transfer, their density, and lifetime were found to rely on the layout layers in the core-shell nanostructure. In optimal core-shell design, Bi2O3 collects holes from TiO2, leaving electrons free to react and increase by 5 times the photocatalytic efficiency toward H2 generation. This study provides new insight into the importance of the design and elaboration of optimal heterojunction based on the photocatalyst system to improve the photocatalytic activity.

关键词: photocatalysis     core-shell     heterojunction     H2     TiO2     Bi2O3    

H<sub>2sub> 对Pt-Ba-Ce /γ-Al<sub>2sub>O<sub>3sub> 催化剂NO<sub>xsub> 存储和还原机理的影响研究 Article

王攀, 裔静, 孙川, 罗鹏, 雷利利

《工程(英文)》 2019年 第5卷 第3期   页码 568-575 doi: 10.1016/j.eng.2019.02.005

摘要:

本研究采用浸渍法制备了Pt-Ba-Ce/γ-Al<sub>2sub>O<sub>3sub>催化剂,利用实验评价了H<sub>2sub> 对NSR(NO<sub>xsub> storage and reduction)催化剂存储和还原机理的影响,并采用综合表征技术研究了Pt-Ba-Ce /γ-Al<sub>2sub>O<sub>3sub结果表明,透射电子显微镜(TEM)显示X 射线衍射(XRD)光谱中观察到的PtO<sub>xsub>、CeO<sub>2sub> 和BaCO<sub>3sub> 峰很好地分散在γ-Al<sub>2sub>O<sub>3sub> 上,X 射线光电子能谱(XPS)检测到Ce3+ 和Ce4+ 之间的差异,Ce3+ 和Ce4+ 促进了活性氧在催化剂上的迁移。适当增加H<sub>2sub>量加速了硝酸盐或亚硝酸盐的分解,有利于NO<sub>xsub> 存储-还原,并促进了下一循环NSR吸附位点的再生。

关键词: Pt–Ba–Ce/γ-Al<sub>2sub>O<sub>3sub> 催化剂,物理化学性质,NO<sub>xsub>存储和还原,NO<sub>xsub> 排放,H<sub>2sub> 还原剂    

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    

Highly selective catalytic hydrodeoxygenation of guaiacol to cyclohexane over Pt/TiO

Zhong HE,Xianqin WANG

《化学科学与工程前沿(英文)》 2014年 第8卷 第3期   页码 369-377 doi: 10.1007/s11705-014-1435-9

摘要: Catalysts Pt/TiO and NiMo/Al O are highly active and selective for the hydrodeoxygenation of guaiacol in a fixed bed reactor at 300 °C and 7.1 MPa, leading to the hydrogenation of aromatic ring, followed by demethylation and dehydroxylation to produce cyclohexane. For a complete hydrodeoxygenation of guaiacol, metal sites and acid sites are required. NiMo/Al O and Pt/Al O are more active and selective for cyclohexane formation as compared with Pt/TiO at 285 °C and 4 MPa. However, Pt/TiO is stable while the other two catalysts deactivate due to the nature and amount of coke formation during the reaction.

关键词: Pt/TiO2     NiMo/Al2O3     Pt/Al2O3     bio-oil     hydrodeoxygenation     guaiacol     cyclohexane    

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    

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    

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    

标题 作者 时间 类型 操作

Effective regeneration of thermally deactivated commercial V-W-Ti catalysts

Xuesong SHANG, Jianrong LI, Xiaowei YU, Jinsheng CHEN, Chi HE

期刊论文

Chemical deactivation of V

Xiaodong WU, Wenchao YU, Zhichun SI, Duan WENG

期刊论文

Characterization and performance of V

Caiting LI, Qun LI, Pei LU, Huafei CUI, Guangming ZENG

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

On the monolayer dispersion behavior of Co<sub>3sub>O<sub>4sub> on HZSM-5 support: designing applicablecatalysts for selective catalytic reduction of nitrogen oxides by ammonia

期刊论文

Simultaneous removal of NO and chlorobenzene on VO/TiO granular catalyst: Kinetic study and performance

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

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

Interfacial charge transfer and photocatalytic activity in a reverse designed BiO/TiO core-shell

期刊论文

H<sub>2sub> 对Pt-Ba-Ce /γ-Al<sub>2sub>O<sub>3sub> 催化剂NO<sub>xsub> 存储和还原机理的影响研究

王攀, 裔静, 孙川, 罗鹏, 雷利利

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

Highly selective catalytic hydrodeoxygenation of guaiacol to cyclohexane over Pt/TiO

Zhong HE,Xianqin WANG

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

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

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