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Denitrification performance and sulfur resistance mechanism of Sm–Mn catalyst for low temperature NH-SCR

《化学科学与工程前沿(英文)》 2023年 第17卷 第5期   页码 617-633 doi: 10.1007/s11705-022-2258-8

摘要: MnOx and Sm–Mn catalysts were prepared with the coprecipitation method, and they showed excellent activities and sulfur resistances for the selective catalytic reduction of NOx by NH3 between 50 and 300 °C in the presence of excess oxygen. 0.10Sm–Mn catalyst indicated better catalytic activity and sulfur resistance. Additionally, the Sm doping led to multi-aspect impacts on the phases, morphology structures, gas adsorption, reactions process, and specific surface areas. Therefore, it significantly enhances the NO conversion, N2 selectivity, and sulfur resistance. Based on various experimental characterization results, the reaction mechanism of catalysts and the effect of SO2 on the reaction process about the catalysts were extensively explored. For 0.10Sm–Mn catalyst, manganese sulfate and sulfur ammonium cannot be generated broadly under the influence of SO2 and the amount of surface adsorbed oxygen. The Bronsted acid sites strengthen significantly due to the addition of SO2, enhancing the sulfur resistance of the 0.10Sm–Mn catalyst.

关键词: MnOx     Sm–Mn     catalyst     NH3-SCR     sulfur resistance    

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    

Piezocatalytic performance of FeO−BiMoO catalyst for dye degradation

《化学科学与工程前沿(英文)》 2023年 第17卷 第6期   页码 716-725 doi: 10.1007/s11705-022-2265-9

摘要: A Fe2O3−Bi2MoO6 heterojunction was synthesized via a hydrothermal method. Scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray, powder X-ray diffraction, Fourier transform infrared spectroscopy and ultra-violet−visible near-infrared spectrometry were performed to measure the structures, morphologies and optical properties of the as-prepared samples. The various factors that affected the piezocatalytic property of composite catalyst were studied. The highest rhodamine B degradation rate of 96.6% was attained on the 3% Fe2O3−Bi2MoO6 composite catalyst under 60 min of ultrasonic vibration. The good piezocatalytic activity was ascribed to the formation of a hierarchical flower-shaped microsphere structure and the heterostructure between Fe2O3 and Bi2MoO6, which effectively separated the ultrasound-induced electron–hole pairs and suppressed their recombination. Furthermore, a potential piezoelectric catalytic dye degradation mechanism of the Fe2O3−Bi2MoO6 catalyst was proposed based on the band potential and quenching effect of radical scavengers. The results demonstrated the potential of using Fe2O3−Bi2MoO6 nanocomposites in piezocatalytic applications.

关键词: piezocatalysis     Fe2O3−Bi2MoO6     dye decomposition     ultrasonic vibration    

Ni/MgO catalyst prepared via dielectric-barrier discharge plasma with improved catalytic performance

Yan LI,Zhehao WEI,Yong WANG

《化学科学与工程前沿(英文)》 2014年 第8卷 第2期   页码 133-140 doi: 10.1007/s11705-014-1422-1

摘要: A Ni/MgO catalyst was prepared via novel dielectric-barrier discharge (DBD) plasma decomposition method. The combined characterization of Brunauer-Emmett-Teller measurement, X-ray diffraction, hydrogen temperature-programmed reduction and transmission electron microscopy shows that DBD plasma treatment enhances the support-metal interaction of Ni/MgO catalyst and facilitates the formation of smaller Ni particles. Sphere-like Ni particles form on plasma treated Ni/MgO catalysts. The plasma treated Ni/MgO catalyst shows a significantly improved low temperature activity and good stability for CO reforming of methane to syngas.

关键词: CO2 reforming     methane     dielectric-barrier discharge (DBD)     plasma     Ni/MgO    

Catalytic performance of Co-Mo-Ce-K/γ-Al

Yuqiong ZHAO, Yongfa ZHANG

《化学科学与工程前沿(英文)》 2010年 第4卷 第4期   页码 457-460 doi: 10.1007/s11705-010-0524-7

摘要: The catalytic performance of Co-Mo-Ce-K/γ-Al O catalyst for the shift reaction of CO in coke oven gas is investigated using X-ray diffraction (XRD) and temperature-programmed reduction (TPR). The results indicate that Ce and K have a synergistic effect on promoting the catalytic activity, and the Co-Mo-Ce-K/γ-Al O catalyst with 3.0 wt-% CeO and 6.0 wt-% K O exhibits the highest activity. CeO favors Co dispersion and mainly produces an electronic effect. TPR characterization results indicate that the addition of CeO -K O in the Co-Mo-Ce-K/γ-Al O catalyst decreases the reduction temperature of active components, and part of octahedrally coordinated Mo transforms into tetrahedrally coordinated Mo , which has a close relationship with the catalytic activity.

关键词: coke oven gas     water gas shift reaction     sulfur-tolerant catalyst     cerium dioxide    

Review of characterization and modeling of polymer electrolyte fuel cell catalyst layer: The blessing

Jun HUANG, Zhe LI, Jianbo ZHANG

《能源前沿(英文)》 2017年 第11卷 第3期   页码 334-364 doi: 10.1007/s11708-017-0490-6

摘要: Ionomer impregnation represents a milestone in the evolution of polymer electrolyte fuel cell (PEFC) catalyst layers. Ionomer acts as the binder, facilitates proton transport, and thereby drastically improves catalyst utilization and effectiveness. However, advanced morphological and functional characterizations have revealed that up to 60% of Pt nanoparticles can be trapped in the micropores of carbon support particles. Ionomer clusters and oxygen molecules can hardly enter into micropores, leading to low Pt utilization and effectiveness. Moreover, the ionomer thin-films covering Pt nanoparticles can cause significant mass transport loss especially at high current densities. Ionomer-free ultra-thin catalyst layers (UTCLs) emerge as a promising alternative to reduce Pt loading by improving catalyst utilization and effectiveness, while theoretical issues such as the proton conduction mechanism remain puzzling and practical issues such as the rather narrow operation window remain unsettled. At present, the development of PEFC catalyst layer has come to a crossroads: staying ionomer-impregnated or going ionomer-free. It is always beneficial to look back into the past when coming to a crossroads. This paper addresses the characterization and modeling of both the conventional ionomer-impregnated catalyst layer and the emerging ionomer-free UTCLs, featuring advances in characterizing microscale distributions of Pt particles, ionomer, support particles and unraveling their interactions; advances in fundamental understandings of proton conduction and flooding behaviors in ionomer-free UTCLs; advances in modeling of conventional catalyst layers and especially UTCLs; and discussions on high-impact research topics in characterizing and modeling of catalyst layers.

关键词: polymer electrolyte fuel cell     ultra-thin catalyst layer     electrostatic interactions     characterization and modeling     structure-property-performance relation     water management    

Preparation and influence of performance of anodic catalysts for direct methanol fuel cell

WANG Zhenbo, YIN Geping, SHI Pengfei

《化学科学与工程前沿(英文)》 2007年 第1卷 第1期   页码 20-25 doi: 10.1007/s11705-007-0005-9

摘要: This research aims at increasing the utilization of platinum-ruthenium alloy (Pt-Ru) catalysts and thus lowering the catalyst loading in anodes for methanol electrooxidation. The direct methanol fuel cell s (DMFC) anodic catalysts, Pt-Ru/C, were prepared by chemical reduction with a reducing agent added in two kinds of solutions under different circumstances. The reducing agent was added in hot solution with the protection of inert gases or just air, and in cold solution with inert gases. The catalysts were treated at different temperatures. Their performance was tested by cyclic voltammetry and potentiostatic polarization by utilizing their inherent powder microelectrode in 0.5 mol/L CHOH and 0.5 mol/L HSO solution. The structures and micro-surface images of the catalysts were determined and observed by X-ray diffraction and transmission electron microscopy, respectively. The catalyst prepared in inert gases showed a better catalytic performance for methanol electrooxidation than that prepared in air. It resulted in a more homogeneous distribution of the Pt-Ru alloy in carbon. Its size is small, only about 4.5 nm. The catalytic performance is affected by the order of the reducing agent added. The performance of the catalyst prepared by adding the reductant at constant temperature of the solution is better than that prepared by adding it in the solution at 0?C and then heating it up to the reducing temperature. The structure of the catalyst was modified, and there was an increase in the conversion of ruthenium into the alloyed state and an increase in particle size with the ascension of heat treatment temperature. In addition, the stability of the catalyst was improved after heat treatment.

关键词: catalyst prepared     stability     ascension     potentiostatic polarization     platinum-ruthenium    

Synthesis, characterization and hydrotreating performance of supported tungsten phosphide catalysts

SUN Guida, LI Cuiqing, ZHOU Zhijun, LI Fengyan

《化学科学与工程前沿(英文)》 2008年 第2卷 第2期   页码 155-164 doi: 10.1007/s11705-008-0038-8

摘要: Supported tungsten phosphide catalysts were prepared by temperature-programmed reduction of their precursors (supported phospho-tungstate catalysts) in H and characterized by X-ray diffraction (XRD), BET, temperature-programmed desorption of ammonia (NH-TPD) and X-ray photoelectron spectroscopy (XPS). The reduction-phosphiding processes of the precursors were investigated by thermogravimetry and differential thermal analysis (TG-DTA) and the suitable phosphiding temperatures were defined. The hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) activities of the catalysts were tested by using thiophene, pyridine, dibenzothiophene, carbazole and diesel oil as the feedstock. The TiO, -AlO supports and the Ni, Co promoters could remarkably increase and stabilize active W species on the catalyst surface. A suitable amount of Ni (3%–5%), Co (5%–7%) and V (1%–3%) could increase dispersivity of the W species and the BET surface area of the WP/-AlO catalyst. The WP/-AlO catalyst possesses much higher thiophene HDS and carbazole HDN activities and the WP/TiO catalyst has much higher dibenzothiophene (DBT) HDS and pyridine HDN activities. The Ni, Co and V can obviously promote the HDS activity and inhibit the HDN activity of the WP/-AlO catalyst. The G-Ni5 catalyst possesses a much higher diesel oil HDS activity than the sulphided industrial NiW/-AlO catalyst. In general, a support or promoter in the WP/-AlO catalyst which can increase the amount and dispersivity of the active W species can promote its HDS and HDN activities.

关键词: tungsten phosphide     differential thermal     catalyst surface     industrial NiW/-AlO     general    

Nitrogen-doped graphene approach to enhance the performance of a membraneless enzymatic biofuel cell

Alireza AHMADIAN YAZDI, Jie XU

《能源前沿(英文)》 2018年 第12卷 第2期   页码 233-238 doi: 10.1007/s11708-018-0529-3

摘要: Heteroatom-doping of pristine graphene is an effective route for tailoring new characteristics in terms of catalytic performance which opens up potentials for new applications in energy conversion and storage devices. Nitrogen-doped graphene (N-graphene), for instance, has shown excellent performance in many electrochemical systems involving oxygen reduction reaction (ORR), and more recently glucose oxidation. Owing to the excellent sensitivity of N-graphene, the development of highly sensitive and fast-response enzymatic biosensors is made possible. However, a question that needs to be addressed is whether or not improving the anodic response to glucose detection leads to a higher overall performance of enzymatic biofuel cell (eBFC). Thus, here we first synthesized N-graphene via a catalyst-free single-step thermal process, and made use of it as the biocatalyst support in a membraneless eBFC to identify its role in altering the performance characteristics. Our findings demonstrate that the electron accepting nitrogen sites in the graphene structure enhances the electron transfer efficiency between the mediator (redox polymer), redox active site of the enzymes, and electrode surface. Moreover, the best performance in terms of power output and current density of eBFCs was observed when the bioanode was modified with highly doped N-graphene.

关键词: enzymatic fuel cell     nitrogen-doped graphene     reduced graphene oxide     catalyst-free synthesis    

Novel synthetic approaches and TWC catalytic performance of flower-like Pt/CeO

Zongcheng ZHAN,Xiaojun LIU,Dongzhu MA,Liyun SONG,Jinzhou LI,Hong HE,Hongxing DAI

《环境科学与工程前沿(英文)》 2014年 第8卷 第4期   页码 483-495 doi: 10.1007/s11783-013-0595-z

摘要: A novel Ultrasonic Assisted Membrane Reduction (UAMR)-hydrothermal method was used to prepare flower-like Pt/CeO catalysts. The texture, physical/chemical properties, and reducibility of the flower-like Pt/CeO catalysts were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), N adsorption, and hydrogen temperature programmed reduction (H -TPR) techniques. The catalytic performance of the catalysts for treating automobile emission was studied relative to samples prepared by the conventional wetness impregnation method. The Pt/CeO catalysts fabricated by this novel method showed high specific surface area and metal dispersion, excellent three-way catalytic activity, and good thermal stability. The strong interaction between the Pt nanoparticles and CeO improved the thermal stability. The Ce ions were incorporated into the surfactant chains and the Pt nanoparticles were stabilized through an exchange reaction of the surface hydroxyl groups. The SEM results demonstrated that the Pt/CeO catalysts had a typical three-dimensional (3D) hierarchical porous structure, which was favorable for surface reaction and enhanced the exposure degree of the Pt nanoparticles. In brief, the flower-like Pt/CeO catalysts prepared by UAMR-hydrothermal method exhibited a higher Pt metal dispersion, smaller particle size, better three-way catalytic activity, and improved thermal stability versus conventional materials.

关键词: three-way catalyst     flower-like     Ultrasonic Assisted Membrane Reduction (UAMR)     Pt nanoparticles    

Modeling nanostructured catalyst layer in PEMFC and catalyst utilization

Jiejing ZHANG, Pengzhen CAO, Li XU, Yuxin WANG

《化学科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 297-302 doi: 10.1007/s11705-011-1201-1

摘要: A lattice model of the nanoscaled catalyst layer structure in proton exchange membrane fuel cells (PEMFC) was established by Monte Carlo method. The model takes into account all the four components in a typical PEMFC catalyst layer: platinum (Pt), carbon, ionomer and pore. The elemental voxels in the lattice were set fine enough so that each average sized Pt particulate in Pt/C catalyst can be represented. Catalyst utilization in the modeled catalyst layer was calculated by counting up the number of facets of Pt voxels where “three phase contact” are met. The effects of some factors, including porosity, ionomer content, Pt/C particle size and Pt weight percentage in the Pt/C catalyst, on catalyst utilization were investigated and discussed.

关键词: catalyst layer     PEM fuel cell     lattice model     Monte Carlo method     catalyst utilization    

Oxidant or catalyst for oxidation?

Jianzhi Huang, Huichun Zhang

《环境科学与工程前沿(英文)》 2019年 第13卷 第5期 doi: 10.1007/s11783-019-1158-8

摘要: Manganese oxides (MnOx) have been demonstrated to be effective materials to activate Oxone (i.e., PMS) to degrade various contaminants. However, the contribution of direct oxidation by MnOx to the total contaminant degradation under acidic conditions was often neglected in the published work, which has resulted in different and even conflicting interpretations of the reaction mechanisms. Here, the role of MnOx (as both oxidants and catalysts) in the activation of Oxone was briefly discussed. The findings offered new insights into the reaction mechanisms in PMS-MnOx and provided a more accurate approach to examine contaminant degradation for water/wastewater treatment.

关键词: Peroxymonosulfate     Manganese oxides     Catalyst     Oxidant    

Monte Carlo simulation of the PEMFC catalyst layer

WANG Hongxing, CAO Pengzhen, WANG Yuxin

《化学科学与工程前沿(英文)》 2007年 第1卷 第2期   页码 146-150 doi: 10.1007/s11705-007-0027-3

摘要: The performance of the polymer electrolyte membrane fuel cell (PEMFC) is greatly controlled by the structure of the catalyst layer. Low catalyst utilization is still a significant obstacle to the commercialization of the PEMFC. In order to get a fundamental understanding of the electrode structure and to find the limiting factor in the low catalyst utilization, it is necessary to develop the mechanical model on the effect of catalyst layer structure on the catalyst utilization and the performance of the PEMFC. In this work, the structure of the catalyst layer is studied based on the lattice model with the Monte Carlo simulation. The model can predict the effects of some catalyst layer components, such as Pt/C catalyst, electrolyte and gas pores, on the utilization of the catalyst and the cell performance. The simulation result shows that the aggregation of conduction grains can greatly affect the degree of catalyst utilization. The better the dispersion of the conduction grains, the larger the total effective area of the catalyst is. To achieve higher utilization, catalyst layer components must be distributed by means of engineered design, which can prevent aggregation.

关键词: catalyst utilization     PEMFC     commercialization     Pt/C catalyst     conduction    

Dendritic BiVO4 decorated with MnOx co-catalyst as an efficient hierarchical catalyst for photocatalytic

Jin Yang, Xuelian Liu, Hongbin Cao, Yanchun Shi, Yongbing Xie, Jiadong Xiao

《化学科学与工程前沿(英文)》 2019年 第13卷 第1期   页码 185-191 doi: 10.1007/s11705-018-1713-z

摘要: An appropriate co-catalyst can significantly promote the photocatalytic efficacy, but this has been seldom studied in the visible-light photocatalysis combined with ozone, namely photocatalytic ozonation. In this work, a dendritic bismuth vanadium tetraoxide (BiVO ) material composited with highly dispersed MnO nanoparticles was synthesized, and its catalytic activity is 86.6% higher than bare BiVO in a visible light and ozone combined process. Catalytic ozonation experiments, ultra-violet-visible (UV-Vis) diffuse reflectance spectra and photoluminescence spectra jointly indicate that MnO plays a triple role in this process. MnO strengthens the light adsorption and promotes the charge separation on the composite material, and it also shows good activity in catalytic ozonation. The key reactive species in this process is ·OH, and various pathways for its generation in this process is proposed. This work provides a new direction of catalyst preparation and pushes forward the application of photocatalytic ozonation in water treatment.

关键词: manganese oxide     bismuth vanadium tetraoxide     photocatalytic ozonation     hydroxyl radical     co-catalyst    

Insight into the promotion mechanism of activated carbon on the monolithic honeycomb red mud catalyst

《环境科学与工程前沿(英文)》 2021年 第15卷 第5期 doi: 10.1007/s11783-020-1337-7

摘要:

• Activated carbon was proposed to be an efficient accelerant for molded red mud catalyst.

关键词: NOx     Selective catalytic reduction     Iron-based catalyst     Red mud     Monolithic catalyst     Activated carbon    

标题 作者 时间 类型 操作

Denitrification performance and sulfur resistance mechanism of Sm–Mn catalyst for low temperature NH-SCR

期刊论文

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

期刊论文

Piezocatalytic performance of FeO−BiMoO catalyst for dye degradation

期刊论文

Ni/MgO catalyst prepared via dielectric-barrier discharge plasma with improved catalytic performance

Yan LI,Zhehao WEI,Yong WANG

期刊论文

Catalytic performance of Co-Mo-Ce-K/γ-Al

Yuqiong ZHAO, Yongfa ZHANG

期刊论文

Review of characterization and modeling of polymer electrolyte fuel cell catalyst layer: The blessing

Jun HUANG, Zhe LI, Jianbo ZHANG

期刊论文

Preparation and influence of performance of anodic catalysts for direct methanol fuel cell

WANG Zhenbo, YIN Geping, SHI Pengfei

期刊论文

Synthesis, characterization and hydrotreating performance of supported tungsten phosphide catalysts

SUN Guida, LI Cuiqing, ZHOU Zhijun, LI Fengyan

期刊论文

Nitrogen-doped graphene approach to enhance the performance of a membraneless enzymatic biofuel cell

Alireza AHMADIAN YAZDI, Jie XU

期刊论文

Novel synthetic approaches and TWC catalytic performance of flower-like Pt/CeO

Zongcheng ZHAN,Xiaojun LIU,Dongzhu MA,Liyun SONG,Jinzhou LI,Hong HE,Hongxing DAI

期刊论文

Modeling nanostructured catalyst layer in PEMFC and catalyst utilization

Jiejing ZHANG, Pengzhen CAO, Li XU, Yuxin WANG

期刊论文

Oxidant or catalyst for oxidation?

Jianzhi Huang, Huichun Zhang

期刊论文

Monte Carlo simulation of the PEMFC catalyst layer

WANG Hongxing, CAO Pengzhen, WANG Yuxin

期刊论文

Dendritic BiVO4 decorated with MnOx co-catalyst as an efficient hierarchical catalyst for photocatalytic

Jin Yang, Xuelian Liu, Hongbin Cao, Yanchun Shi, Yongbing Xie, Jiadong Xiao

期刊论文

Insight into the promotion mechanism of activated carbon on the monolithic honeycomb red mud catalyst

期刊论文