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PM-support interfacial effect and oxygen mobility in Pt, Pd or Rh-loaded (Ce,Zr,La)O catalysts

《环境科学与工程前沿(英文)》 2021年 第15卷 第4期 doi: 10.1007/s11783-020-1369-z

摘要:

• Pt/CZL exhibits the optimum catalytic performance for HC and NOx elimination.

关键词: Precious metal-loaded (Ce     Zr     La)O2 catalysts     Oxygen mobility     Catalytic performance    

NO oxidation over Co-La catalysts and NO

Tiejun Zhang,Jian Li,Hong He,Qianqian Song,Quanming Liang

《环境科学与工程前沿(英文)》 2017年 第11卷 第2期 doi: 10.1007/s11783-017-0906-x

摘要: The Co-La catalyst (pH= 1) exhibited maximum NO conversion of 43% at 180°C. Acid modified catalyst enhanced the resistance to SO . The formed sulfates may block the pore structure of the catalyst. The NO conversion of compact SCR was 91% at 180°C at the highest space velocity. A series of Co-La catalysts were prepared using the wet impregnation method and the synthesis of catalysts were modified by controlling pH with the addition of ammonium hydroxide or oxalic solution. All the catalysts were systematically investigated for NO oxidation and SO resistance in a fixed bed reactor and were characterized by Brunanuer–Emmett–Teller (BET) method, Fourier Transform infrared spectroscopy (FTIR), X–ray diffraction (XRD), Thermogravimetric (TG) and Ion Chromatography (IC). Among the catalysts, the one synthesized at pH= 1 exhibited the maximum NO conversion of 43% at 180°C. The activity of the catalyst was significantly suppressed by the existence of SO (300 ppm) at 220°C. Deactivation may have been associated with the generation of cobalt sulfate, and the SO adsorption quantity of the catalyst might also have effected sulfur resistance. In the case of the compact selective catalytic reduction (SCR), the activity increased from 74% to 91% at the highest gas hourly space velocity (GHSV) of 300000 h when the NO catalyst maintained the highest activity, in excess of 50% more than that of the standard SCR.

关键词: NO catalytic oxidation     pH effect     Low temperature     Sulfur dioxide     High space velocity     SCR    

Effects of MgO promoter on properties of Ni/Al2O3 catalysts for partial oxidation of methane to syngas

QIU Yejun, CHEN Jixiang, ZHANG Jiyan

《化学科学与工程前沿(英文)》 2007年 第1卷 第2期   页码 167-171 doi: 10.1007/s11705-007-0031-7

摘要: The effects of MgO promoter on the physico-chemical properties and catalytic performance of Ni/AlO catalysts for the partial oxidation of methane to syngas were studied by means of BET, XRD, H-TPR, TEM and performance evaluation. It was found that the MgO promoter benefited from the uniformity of nickel species in the catalysts, inhibited the formation of NiAlO spinel and improved the interaction between nickel species and support. These results were related to the formation of NiO MgO solid solution and MgAlO spinel. Moreover, for the catalysts with a proper amount of MgO promoter, the nickel dispersiveness was enhanced, therefore making their catalytic performance in methane partial oxidation improved. However, the excessive MgO promoter exerted a negative effect on the catalytic performance. Meanwhile, the basicity of MgO promoted the reversed water gas shift reaction, which led to an increase in CO selectivity and a decrease in H2 selectivity. The suitable content of MgO promoter in Ni/AlO catalyst was ?7 wt-%.

关键词: excessive     selectivity     decrease     dispersiveness     physico-chemical    

Properties of La1-xCexCoO3 system perovskite-type catalysts for diesel engine exhaust removal

GONG Cairong, FAN Guoliang, HOU Yanfeng, ZHANG Zhongrong, SONG Chonglin, HUANG Qifei

《化学科学与工程前沿(英文)》 2007年 第1卷 第1期   页码 6-10 doi: 10.1007/s11705-007-0002-z

摘要: A series of complex oxide LaCeCoO catalysts was synthesized at a low temperature through a combustion process, in which x is among 0, 0.1, 0.2, 0.4 and 0.6 corresponding to the quantity of La partial substitution by Ce. The catalysts were characterized for phase composition using chemical analysis and X-ray diffraction. The catalytic activity of the catalysts in removal of NO, total hydrocarbon (THC) and particulate matter (PM) from diesel exhaust gases were examined in detail using temperature-programmed reaction technique. The results show that after partial substitution of La with Ce, the oxygen vacancy concentration increases significantly and a Co-Co system is formed. Consequently, the catalytic activity in the removal of THC and NO is significantly improved. But for the PM, the effect is not so obvious. The possible catalytic mechanism for this was presented. It is also worth noting that the doped catalysts showed good stability.

关键词: catalytic mechanism     combustion     corresponding     LaCeCoO     catalytic activity    

Size and shape effects of MnFeO nanoparticles as catalysts for reductive degradation of dye pollutants

《环境科学与工程前沿(英文)》 2021年 第15卷 第5期   页码 108-171 doi: 10.1007/s11783-021-1396-4

摘要: The magnetic nanoparticles that are easy to recycle have tremendous potential as a suitable catalyst for environmental toxic dye pollutant degradation. Rationally engineering shapes and tailoring the size of nanocatalysts are regarded as an effective manner for enhancing performances. Herein, we successfully synthesized three kinds of MnFe2O4 NPs with distinctive sizes and shapes as catalysts for reductive degradation of methylene blue, rhodamine 6G, rhodamine B, and methylene orange. It was found that the catalytic activities were dependent on the size and shape of the MnFe2O4 NPs and highly related to the surface-to-volume ratio and atom arrangements. Besides, all these nanocatalysts exhibit selectivity to different organic dyes, which is beneficial for their practical application in dye pollutant treatment. Furthermore, the MnFe2O4 NPs could be readily recovered by a magnet and reused more than ten times without appreciable loss of activity. The size and shape effects of MnFe2O4 nanoparticles demonstrated in this work not only accelerate further understanding the nature of nanocatalysts but also contribute to the precise design of nanoparticles catalyst for pollutant degradation.

关键词: Dye degradation     MnFe2O4 nanoparticles     Size and shape-control    

H2 对Pt-Ba-Ce /γ-Al2O3 催化剂NOx 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-Al2O3催化剂,利用实验评价了H2 对NSR(NOx 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-Al2O3x、CeO2 和BaCO3 峰很好地分散在γ-Al2O3 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H2量加速了硝酸盐或亚硝酸盐的分解,有利于NOx 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-Al2O3 催化剂,物理化学性质,NOx存储和还原,NOx 排放,H2 还原剂    

On the monolayer dispersion behavior of Co3O4 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    

CO2 methanation and co-methanation of CO and CO2 over Mn-promoted Ni/Al2O3 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    

Tailoring the simultaneous abatement of methanol and NO on Sb-Ce-Zr catalysts via copper modification

《环境科学与工程前沿(英文)》 2022年 第16卷 第10期 doi: 10.1007/s11684-022-1565-0

摘要:

● Cu addition enhances CH3OH oxidation and alleviates its inhibitory effect on SCR.

关键词: Copper modification     Sb-CeZr2Ox catalyst     NOx     Methanol     Simultaneous removal    

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    

Tuning of the active phase structure and hydrofining performance of alumina-supported tri-metallic WMoNi catalysts

Shufeng Shan, Haiyan Liu, Gang Shi, Xiaojun Bao

《化学科学与工程前沿(英文)》 2018年 第12卷 第1期   页码 59-69 doi: 10.1007/s11705-017-1686-3

摘要: The effects of phosphorus on the structure and hydrofining performance of tri-metallic WMoNi/Al O catalysts prepared with W/Mo-based hybrid precursor nanocrystals were investigated. The incorporation of phosphorus weakened the metal-support interactions (MSIs) and facilitated the formation of more synergetic NiWMoS phases with higher stacks. Catalytic tests using a fluid catalytic cracking diesel fuel showed that the changes in the MSIs and the morphology of the active phases had a more positive effect on the hydrodenitrogenation activity than on the hydrodesulfurization activity. In contrast, when phosphorus was incorporated into a tri-metallic WMoNiP/Al O catalyst prepared by a conventional incipient impregnation method, the MSIs decreased causing aggregation of the metal species which resulted in poorer hydrofining performance of the catalyst. These results show that incorporating phosphorus into a WMoNi/Al O catalyst can finely tune the structure of the active phase to enhance the hydrogenation and hydrodenitrogenation activity of the resulting tri-metallic catalyst.

关键词: fluid catalytic cracking diesel     hydrofining performance     WMoNiP/Al2O3     synergetic effect and structure of NiWMoS phases    

Complete oxidation of methane on CoO-SnO catalysts

Xingfu TANG , Jiming HAO , Junhua LI ,

《环境科学与工程前沿(英文)》 2009年 第3卷 第3期   页码 265-270 doi: 10.1007/s11783-009-0019-2

摘要: CoO-SnO hybrid oxides were prepared by the coprecipitation method and were used to oxidate methane (CH) in presence of oxygen. The CoO-SnO with a molar ratio of Co/(Co+Sn) at 0.75 exhibited the highest catalytic activity among all the CoO-SnO hybrid oxides. Experimental results showed that the catalysts were considerably stable in the CH combustion reaction, and were verified by X-ray photoelectron spectra (XPS). It was found that CoO was the active species, and SnO acted as a support or a promoting component in the CoO-SnO hybrid oxides. The surface area was not a major factor that affected catalytic activity. The hydrogen temperature-programmed reduction (H-TPR) results demonstrated that the interaction between cobalt and tin oxides accelerated the mobility of oxygen species of CoO-SnO, leading to higher catalytic activity.

关键词: Co3O4-SnO2     complete oxidation     methane (CH4)    

Rh2O3/hexagonal CePO4 nanocatalysts for N2O 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    

Influence of crystalline phase of Li-Al-O oxides on the activity of Wacker-type catalysts in dimethyl

Yadong GE, Yuanyuan DONG, Shengping WANG, Yujun ZHAO, Jing LV, Xinbin MA

《化学科学与工程前沿(英文)》 2012年 第6卷 第4期   页码 415-422 doi: 10.1007/s11705-012-1214-4

摘要: The catalysts supported on LiAl O (spinel) for vapor phase synthesis of dimethyl carbonate (DMC) from methyl nitrite (MN) have been studied. Their catalytic activities on supports prepared by different methods were evaluated in a continuous reactor. The samples were characterized by powder X-ray diffraction, N adsorption-desorption isotherms, fourier transform infrared spectroscopy and temperature-programmed reduction of H . Li/Al molar ratio and calcination temperature greatly influence the structure of crystalline phase of Li-Al-O oxides. Desirable LiAl O (spinel) was formed at 800°C, while LiAl O (primitive cube) formed at 900°C is undesirable for the reaction. A high Li/Al molar ratio, which was related with LiAlO , also slowed the reaction rate. The electron transfer ability and the interaction with active component are the important properties of the spinel-based supports. The CuCl -PdCl /LiAl O (spinel) with better electron transfer ability and low Pd reduction temperature exhibited a better catalytic ability.

关键词: Wacker-type catalyst     dimethyl carbonate     methyl nitrite     spinel    

Investigation of fluorescence characterization and electrochemical behavior on the catalysts of nanosized

Chang-Mao HUNG, Wen-Liang LAI, Jane-Li LIN

《环境科学与工程前沿(英文)》 2013年 第7卷 第3期   页码 428-434 doi: 10.1007/s11783-013-0517-0

摘要: This work describes the environmentally friendly technology for oxidation of ammonia (NH ) to form nitrogen at temperatures range from 423K to 673K by selective catalytic oxidation (SCO) over a nanosized Pt-Rh/γ-Al O catalyst prepared by the incipient wetness impregnation method of hexachloroplatinic acid (H PtCl ) and rhodium (III) nitrate (Rh(NO ) ) with γ-Al O in a tubular fixed-bed flow quartz reactor (TFBR). The characterization of catalysts were thoroughly measured using transmission electron microscopy (TEM), three-dimensional excitation-emission fluorescent matrix (EEFM) spectroscopy, UV-Vis absorption, dynamic light-scattering (DLS), zeta potential meter, and cyclic voltammetry (CV). The results demonstrated that at a temperature of 673K and an oxygen content of 4%, approximately 99% of the NH was removed by catalytic oxidation over the nanosized Pt-Rh/γ-Al O catalyst. N was the main product in NH -SCO process. Further, it reveals that the oxidation of NH was proceeds by the over-oxidation of NH into NO, which was conversely reacted with the NH to yield N . Therefore, the application of nanosized Pt-Rh/γ-Al O catalyst can significantly enhance the catalytic activity toward NH oxidation. One fluorescent peak for fresh catalyst was different with that of exhausted catalyst. It indicates that EEFM spectroscopy was proven to be an appropriate and effective method to characterize the Pt clusters in intrinsic emission from nanosized Pt-Rh/γ-Al O catalyst. Results obtained from the CV may explain the significant catalytic activity of the catalysts.

关键词: ammonia (NH3)     nanosized Pt-Rh/γ-Al2O3 catalyst     excitation-emission fluorescent matrix (EEFM)     selective catalytic oxidation (SCO)     tubular fixed-bed reactor (TFBR)    

标题 作者 时间 类型 操作

PM-support interfacial effect and oxygen mobility in Pt, Pd or Rh-loaded (Ce,Zr,La)O catalysts

期刊论文

NO oxidation over Co-La catalysts and NO

Tiejun Zhang,Jian Li,Hong He,Qianqian Song,Quanming Liang

期刊论文

Effects of MgO promoter on properties of Ni/Al2O3 catalysts for partial oxidation of methane to syngas

QIU Yejun, CHEN Jixiang, ZHANG Jiyan

期刊论文

Properties of La1-xCexCoO3 system perovskite-type catalysts for diesel engine exhaust removal

GONG Cairong, FAN Guoliang, HOU Yanfeng, ZHANG Zhongrong, SONG Chonglin, HUANG Qifei

期刊论文

Size and shape effects of MnFeO nanoparticles as catalysts for reductive degradation of dye pollutants

期刊论文

H2 对Pt-Ba-Ce /γ-Al2O3 催化剂NOx 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

On the monolayer dispersion behavior of Co3O4 on HZSM-5 support: designing applicablecatalysts for selective catalytic reduction of nitrogen oxides by ammonia

期刊论文

CO2 methanation and co-methanation of CO and CO2 over Mn-promoted Ni/Al2O3 catalysts

Kechao Zhao,Zhenhua Li,Li Bian

期刊论文

Tailoring the simultaneous abatement of methanol and NO on Sb-Ce-Zr catalysts via copper modification

期刊论文

Characterization and performance of V

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

期刊论文

Tuning of the active phase structure and hydrofining performance of alumina-supported tri-metallic WMoNi catalysts

Shufeng Shan, Haiyan Liu, Gang Shi, Xiaojun Bao

期刊论文

Complete oxidation of methane on CoO-SnO catalysts

Xingfu TANG , Jiming HAO , Junhua LI ,

期刊论文

Rh2O3/hexagonal CePO4 nanocatalysts for N2O decomposition

Huan Liu, Zhen Ma

期刊论文

Influence of crystalline phase of Li-Al-O oxides on the activity of Wacker-type catalysts in dimethyl

Yadong GE, Yuanyuan DONG, Shengping WANG, Yujun ZHAO, Jing LV, Xinbin MA

期刊论文

Investigation of fluorescence characterization and electrochemical behavior on the catalysts of nanosized

Chang-Mao HUNG, Wen-Liang LAI, Jane-Li LIN

期刊论文