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催化剂 4

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2R-1C模型;嵌入式系统;参数估计;非迭代方法;二次型 1

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New insight into effect of potential on degradation of Fe-N-C catalyst for ORR

Yanyan GAO, Manman QI, Liang HE, Haiping CHEN, Wenzhe LUO, Ming HOU, Zhigang SHAO

《能源前沿(英文)》 2021年 第15卷 第2期   页码 421-430 doi: 10.1007/s11708-021-0727-2

摘要: In recent years, Fe-N-C catalyst is particularly attractive due to its high oxygen reduction reaction (ORR) activity and low cost for proton exchange membrane fuel cells (PEMFCs). However, the durability problems still pose challenge to the application of Fe-N-C catalyst. Although considerable work has been done to investigate the degradation mechanisms of Fe-N-C catalyst, most of them are simply focused on the active-site decay, the carbon oxidation, and the demetalation problems. In fact, the 2e pathway in the ORR process of Fe-N-C catalyst would result in the formation of H O , which is proved to be a key degradation source. In this paper, a new insight into the effect of potential on degradation of Fe-N-C catalyst was provided by quantifying the H O intermediate. In this case, stability tests were conducted by the potential-static method in O saturated 0.1 mol/L HClO . During the tests, H O was quantified by rotating ring disk electrode (RRDE). The results show that compared with the loading voltage of 0.4 V, 0.8 V, and 1.0 V, the catalysts being kept at 0.6 V exhibit a highest H O yield. It is found that it is the combined effect of electrochemical oxidation and chemical oxidation (by aggressive radicals like H O /radicals) that triggered the highest H O release rate, with the latter as the major cause.

关键词: proton exchange membrane fuel cells (PEMFCs)     oxygen reduction reaction (ORR)     Fe-N-C catalyst     potential     H2O2     degradation    

Influence of Fe on electrocatalytic activity of iron-nitrogen-doped carbon materials toward oxygen reduction

Lin LI, Cehuang FU, Shuiyun SHEN, Fangling JIANG, Guanghua WEI, Junliang ZHANG

《能源前沿(英文)》 2022年 第16卷 第5期   页码 812-821 doi: 10.1007/s11708-020-0669-0

摘要: The development of highly active nitrogen-doped carbon-based transition metal (M-N-C) compounds for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs) greatly helps reduce fuel cell cost, thus rapidly promoting their commercial applications. Among different M-N-C electrocatalysts, the series of Fe-N-C materials are highly favored because of their high ORR activity. However, there remains a debate on the effect of Fe, and rare investigations focus on the influence of Fe addition in the second heat treatment usually performed after acid leaching in the catalyst synthesis. It is thus very critical to explore the influences of Fe on the ORR electrocatalytic activity, which will, in turn, guide the design of Fe-N-C materials with enhanced performance. Herein, a series of Fe-N-C electrocatalysts are synthesize and the influence of Fe on the ORR activity are speculated both experimentally and theoretically. It is deduced that the active site lies in the structure of Fe-N , accompanied with the addition of appropriate Fe, and the number of active sites increases without the occurrence of agglomeration particles. Moreover, it is speculated that Fe plays an important role in stabilizing N as well as constituting active sites in the second pyrolyzing process.

关键词: oxygen reduction reaction     Fe-N-C     active sites     Fe addition     second heat treatment    

The performance of nitrate-reducing Fe(II) oxidation processes under variable initial Fe/N ratios: The

《环境科学与工程前沿(英文)》 2021年 第15卷 第4期 doi: 10.1007/s11783-020-1366-2

摘要:

•Bacterially-mediated coupled N and Fe processes examined in incubation experiments.

关键词: Denitrification     N2O emission     Fe(II) oxidation     Fe/N ratio     Fe minerals    

Controllable Fe/HCS catalysts in the Fischer-Tropsch synthesis: Effects of crystallization time

Yifei Wang, Shouying Huang, Xinsheng Teng, Hongyu Wang, Jian Wang, Qiao Zhao, Yue Wang, Xinbin Ma

《化学科学与工程前沿(英文)》 2020年 第14卷 第5期   页码 802-812 doi: 10.1007/s11705-019-1866-4

摘要: The Fischer–Tropsch synthesis (FTS) continues to be an attractive alternative for producing a broad range of fuels and chemicals through the conversion of syngas (H and CO), which can be derived from various sources, such as coal, natural gas, and biomass. Among iron carbides, Fe C, as an active phase, has barely been studied due to its thermodynamic instability. Here, we fabricated a series of Fe C embedded in hollow carbon sphere (HCS) catalysts. By varying the crystallization time, the shell thickness of the HCS was manipulated, which significantly influenced the catalytic performance in the FTS. To investigate the relationship between the geometric structure of the HCS and the physic-chemical properties of Fe species, transmission electron microscopy, X-ray diffraction, N physical adsorption, X-ray photoelectron spectroscopy, hydrogen temperature-programmed reduction, Raman spectroscopy, and Mössbauer spectroscopy techniques were employed to characterize the catalysts before and after the reaction. Evidently, a suitable thickness of the carbon layer was beneficial for enhancing the catalytic activity in the FTS due to its high porosity, appropriate electronic environment, and relatively high Fe C content.

关键词: Fischer–Tropsch synthesis     Fe-based catalyst     Fe2C     hollow carbon sphere     crystallization time    

Floret-like FeN nanoparticle-embedded porous carbon superstructures from a Fe-covalent triazine polymer

《化学科学与工程前沿(英文)》 2023年 第17卷 第5期   页码 525-535 doi: 10.1007/s11705-022-2232-5

摘要: Fe–Nx nanoparticles-embedded porous carbons with a desirable superstructure have attracted immense attention as promising catalysts for electrochemical oxygen reduction reaction. Herein, we employed Fe-coordinated covalent triazine polymer for the fabrication of Fe–Nx nanoparticle-embedded porous carbon nanoflorets (Fe/N@CNFs) employing a hypersaline-confinement-conversion strategy. Presence of tailored N types within the covalent triazine polymer interwork in high proportions contributes to the generation of Fe/N coordination and subsequent Fe–Nx nanoparticles. Owing to the utilization of NaCl crystals, the resultant Fe/N@CNF-800 which was generated by pyrolysis at 800 °C showed nanoflower structure and large specific surface area, which remarkably suppressed the agglomeration of high catalytic active sites. As expect, the Fe/N@CNF-800 exhibited unexpected oxygen reduction reaction catalytic performance with an ultrahigh half-wave potential (0.89 V vs. reversible hydrogen electrode), a dominant 4e transfer approach and great cycle stability (> 92% after 100000 s). As a demonstration, the Fe/N-PCNF-800-assembled zinc–air battery delivered a high open circuit voltage of 1.51 V, a maximum peak power density of 164 mW·cm–2, as well as eminent rate performance, surpassing those of commercial Pt/C. This contribution offers a valuable avenue to exploit efficient metal nanoparticles-based carbon catalysts towards energy-related electrocatalytic reactions and beyond.

关键词: Fe–Nx nanoparticles     hypersaline-confinement conversion     floret-like carbon     covalent triazine polymers     oxygen reduction reaction    

Pd/Fe3O4 supported on bio-waste derived cellulosic-carbon as a nanocatalyst for CC coupling and electrocatalytic

《化学科学与工程前沿(英文)》 2022年 第16卷 第10期   页码 1514-1525 doi: 10.1007/s11705-022-2158-y

摘要: The current work describes the synthesis of a new bio-waste derived cellulosic-carbon supported-palladium nanoparticles enriched magnetic nanocatalyst (Pd/Fe3O4@C) using a simple multi-step process under aerobic conditions. Under mild reaction conditions, the Pd/Fe3O4@C magnetic nanocatalyst demonstrated excellent catalytic activity in the Hiyama cross-coupling reaction for a variety of substrates. Also, the Pd/Fe3O4@C magnetic nanocatalyst exhibited excellent catalytic activity up to five recycles without significant catalytic activity loss in the Hiyama cross-coupling reaction. Also, we explored the use of Pd/Fe3O4@C magnetic nanocatalyst as an electrocatalyst for hydrogen evolution reaction. Interestingly, the Pd/Fe3O4@C magnetic nanocatalyst exhibited better electrochemical activity compared to bare carbon and magnetite (Fe3O4 nanoparticles) with an overpotential of 293 mV at a current density of 10 mA·cm–2.

关键词: bio-waste     cellulosic-carbon     Pd/Fe3O4     Hiyama cross-coupling     hydrogen evolution reaction     recyclability    

Enhancing the efficiency of nitrogen removing bacterial population to a wide range of C:N ratio (1.5:1 to 14:1) for simultaneous C & N removal

《环境科学与工程前沿(英文)》 2022年 第16卷 第8期 doi: 10.1007/s11783-022-1522-y

摘要:

• Simultaneous C & N removal in Methammox occurs at wide C:N ratio.

关键词: Methanogens     Biological Nitrogen Removal (BNR)     Simultaneous     Methammox     C:N ratio    

Probing the catalytic activity of M-N

Fan Ge, Qingan Qiao, Xin Chen, You Wu

《化学科学与工程前沿(英文)》 2021年 第15卷 第5期   页码 1206-1216 doi: 10.1007/s11705-020-2017-7

摘要: In this work, the detailed oxygen reduction reaction (ORR) catalytic performance of M-N O (M= Fe, Co, and Ni; = 1–4) has been explored via the detailed density functional theory method. The results suggest that the formation energy of M-N O shows a good linear relationship with the number of doped O atoms. The adsorption manner of O on M-N O changed from end-on ( = 1 and 2) to side-on ( = 3 and 4), and the adsorption strength gradually increased. Based on the results for binding strength of ORR intermediates and the Gibbs free energy of ORR steps on the studied catalysts, we screened out two highly active ORR catalysts, namely Co-N O and Ni-N O , which possess very small overpotentials of 0.27 and 0.32 V, respectively. Such activities are higher than the precious Pt catalyst. Electronic structure analysis reveals one of the reasons for the higher activity of Co-N O and Ni-N O is that they have small energy gaps and moderate highest occupied molecular orbital energy levels. Furthermore, the results of the density of states reveal that the O doping can improve the electronic structure of the original catalyst to tune the adsorption of the ORR intermediates.

关键词: M-N-C catalyst     oxygen doping     oxygen reduction reaction     catalytic activity     density functional theory    

Fe-Mn-sepiolite as an effective heterogeneous Fenton-like catalyst for the decolorization of reactive

Chengyuan SU,Weiguang LI,Xingzhe LIU,Xiaofei HUANG,Xiaodan YU

《环境科学与工程前沿(英文)》 2016年 第10卷 第1期   页码 37-45 doi: 10.1007/s11783-014-0729-y

摘要: A study of the decolorization of reactive brilliant blue in an aqueous solution using Fe-Mn-sepiolite as a heterogeneous Fenton-like catalyst has been performed. The Fourier transform infrared (FTIR) spectra of the catalyst showed bending vibrations of the Fe-O. The X-ray diffraction (XRD) patterns of the catalyst showed characteristic diffraction peaks of α-Fe O , γ-Fe O and MnO. A four factor central composite design (CCD) coupled with response surface methodology (RSM) was applied to evaluate and optimize the important variables (catalyst addition, hydrogen peroxide dosage, initial pH value and initial dye concentration). When the reaction conditions were catalyst dosage= 0.4 g, [H O ]= 0.3 mL, pH= 2.5, [reactive brilliant blue] = 50 mg·L , and volume of solution= 500 mL at room temperature, the decolorization efficiency of reactive brilliant blue was 91.98% within 60 min. Moreover, the Fe-Mn-sepiolite catalyst had good stability for the degradation of reactive brilliant blue even after six cycles. Leaching of iron ions (<0.4 mg·L ) was observed. The decoloring process was reactive brilliant blue specific via a redox reaction. The benzene ring and naphthalene ring were first oxidized to open ring; these were then oxidized to the alcohol and carboxylic acid. The reactive brilliant blue was decomposed mainly by the attack of ·OH radicals including surface-bound ·OH radicals generated on the catalyst surface.

关键词: Fe-Mn-sepiolite catalyst     heterogeneous Fenton-like     reactive brilliant blue     homogeneous precipitation method     hydroxyl radical    

Controllable synthesis of a large TS-1 catalyst for clean epoxidation of a C=C double bond under mild

《化学科学与工程前沿(英文)》 2023年 第17卷 第6期   页码 772-783 doi: 10.1007/s11705-022-2280-x

摘要: Development of a titanium silicalite-1 (TS-1) catalyst with good crystallinity and a four-coordinate Ti framework is critical for efficient catalytic oxidation reaction under mild conditions. Herein, a size-controlled TS-1 zeolite (TS-1#0.1ACh (acetylcholine)) was synthesized via steam-assisted crystallization by introducing acetylcholine as a crystal growth modifier in the preparation process, and TS-1#0.1ACh was also employed in epoxidations of different substrates containing C=C double bonds. The crystalline sizes of the as-synthesized TS-1#0.1ACh catalysts were controlled with the acetylcholine content, and characterization results showed that the particle sizes of highly crystalline TS-1#0.1ACh zeolite reached 3.0 μm with a good Ti framework. Throughout the synthetic process, the growth rate of the crystals was accelerated by electrostatic interactions between the connected hydroxyl groups of the acetylcholine modifier and the negatively charged skeleton of the pre-zeolites. Furthermore, the TS-1#0.1ACh catalyst demonstrated maximum catalytic activity, good selectivity and high stability during epoxidation of allyl chloride. Importantly, the TS-1#0.1ACh catalyst was also highly versatile and effective with different unsaturated substrates. These findings may provide novel, easily separable and large TS-1 catalysts for efficient and clean industrial epoxidations of C=C double bonds.

关键词: size-controlled TS-1     crystal modifier     steam-assisted crystallization     epoxidation    

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    

Mass Transfer-Promoted Fe2+/Fe3+ Circulation Steered by 3D Flow-Through Co-Catalyst System Toward Sustainable

Weiyang Lv,Hao Li,Jinhui Wang,Lixin Wang,Zenglong Wu,Yuge Wang,Wenkai Song,Wenkai Cheng,Yuyuan Yao,

《工程(英文)》 doi: 10.1016/j.eng.2023.06.010

摘要: Realizing fast and continuous generation of reactive oxygen species (ROSs) via iron-based advanced oxidation processes (AOPs) is significant in the environmental and biological fields. However, current AOPs assisted by co-catalysts still suffer from the poor mass/electron transfer and non-durable promotion effect, giving rise to the sluggish Fe2+/Fe3+ cycle and low dynamic concentration of Fe2+ for ROS production. Herein, we present a three-dimensional (3D) macroscale co-catalyst functionalized with MoS2 to achieve ultra-efficient Fe2+ regeneration (equilibrium Fe2+ ratio of 82.4%) and remarkable stability (more than 20 cycles) via a circulating flow-through process. Unlike the conventional batch-type reactor, experiments and computational fluid dynamics simulations demonstrate that the optimal utilization of the 3D active area under the flow-through mode, initiated by the convection-enhanced mass/charge transfer for Fe2+ reduction and then strengthened by MoS2-induced flow rotation for sufficient reactant mixing, is crucial for oxidant activation and subsequent ROS generation. Strikingly, the flow-through co-catalytic system with superwetting capabilities can even tackle the intricate oily wastewater stabilized by different surfactants without the loss of pollutant degradation efficiency. Our findings highlight an innovative co-catalyst system design to expand the applicability of AOPs based technology, especially in large-scale complex wastewater treatment.

关键词: Advanced oxidation processes     3D co-catalyst     Flow-through mode     Enhanced mass transfer     Complex wastewater treatment    

Effect of noble metal nanoparticle size on CN bond cleavage performance in hydrodenitrogenation: a study

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 1986-2000 doi: 10.1007/s11705-023-2337-5

摘要: Breakage of the C–N bond is a structure sensitive process, and the catalyst size significantly affects its activity. On the active metal nanoparticle scale, the role of catalyst size in C–N bond cleavage has not been clearly elucidated. So, Ru catalysts with variable nanoparticle sizes were obtained by modulating the reduction temperature, and the catalytic activity was evaluated using 1,2,3,4-tetrahydroquinoline and o-propylaniline with different C–N bond hybridization patterns as reactants. Results showed a 13 times higher reaction rate for sp3-hybridized C–N bond cleavage than sp2-hybridized C–N bond cleavage, while the reaction rate tended to increase first and then decrease as the catalyst nanoparticle size increased. Different concentrations of terrace, step, and corner sites were found in different sizes of Ru nanoparticles. The relationship between catalytic site variation and C–N bond cleavage activity was further investigated by calculating the turnover frequency values for each site. This analysis indicates that the variation of different sites on the catalyst is the intrinsic factor of the size dependence of C–N bond cleavage activity, and the step atoms are the active sites for the C–N bond cleavage. When Ru nanoparticles are smaller than 1.9 nm, they have a strong adsorption effect on the reactants, which will affect the catalytic performance of the Ru catalyst. Furthermore, these findings were also confirmed on other metallic Pd/Pt catalysts. The role of step sites in C–N bond cleavage was proposed using the density function theory calculations. The reactants have stronger adsorption energies on the step atoms, and step atoms have d-band center nearer to the Fermi level. In this case, the interaction with the reactant is stronger, which is beneficial for activating the C–N bond of the reactant.

关键词: sp3/sp2-hybridized C–N bond     noble metal nanoparticle     catalytic active site     turnover frequency     DFT    

Atomistic simulations of plasma catalytic processes

Erik C. Neyts

《化学科学与工程前沿(英文)》 2018年 第12卷 第1期   页码 145-154 doi: 10.1007/s11705-017-1674-7

摘要: There is currently a growing interest in the realisation and optimization of hybrid plasma/catalyst systems for a multitude of applications, ranging from nanotechnology to environmental chemistry. In spite of this interest, there is, however, a lack in fundamental understanding of the underlying processes in such systems. While a lot of experimental research is already being carried out to gain this understanding, only recently the first simulations have appeared in the literature. In this contribution, an overview is presented on atomic scale simulations of plasma catalytic processes as carried out in our group. In particular, this contribution focusses on plasma-assisted catalyzed carbon nanostructure growth, and plasma catalysis for greenhouse gas conversion. Attention is paid to what can routinely be done, and where challenges persist.

关键词: atomic scale simulation     plasma-catalyst    

NO hydrogenation to NH over FeCu/TiO catalyst with improved activity

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 1973-1985 doi: 10.1007/s11705-023-2364-2

摘要: Ammonia is crucial in industry and agriculture, but its production is hindered by environmental concerns and energy-intensive processes. Hence, developing an efficient and environmentally friendly catalyst is imperative. In this study, we employed a straightforward and efficient impregnation technique to create various Cu-doped catalysts. Notably, the optimized 10Fe-8Cu/TiO2 catalyst exhibited exceptional catalytic performance in converting NO to NH3, achieving an NO conversion rate exceeding 80% and an NH3 selectivity exceeding 98% at atmospheric pressure and 350 °C. We employed in situ diffuse reflectance Fourier transform infrared spectroscopy and conducted density functional theory calculations to investigate the intermediates and subsequent adsorption. Our findings unequivocally demonstrate that Cu doping enhances the rate-limiting hydrogenation step and lowers the energy barrier for NH3 desorption, thereby resulting in improved NO conversion and enhanced selectivity toward ammonia. This study presents a pioneering approach toward energy-efficient ammonia synthesis and recycling of nitrogen sources.

关键词: NO hydrogenation     synthetic ammonia     10Fe-xCu/TiO2     high selectivity    

标题 作者 时间 类型 操作

New insight into effect of potential on degradation of Fe-N-C catalyst for ORR

Yanyan GAO, Manman QI, Liang HE, Haiping CHEN, Wenzhe LUO, Ming HOU, Zhigang SHAO

期刊论文

Influence of Fe on electrocatalytic activity of iron-nitrogen-doped carbon materials toward oxygen reduction

Lin LI, Cehuang FU, Shuiyun SHEN, Fangling JIANG, Guanghua WEI, Junliang ZHANG

期刊论文

The performance of nitrate-reducing Fe(II) oxidation processes under variable initial Fe/N ratios: The

期刊论文

Controllable Fe/HCS catalysts in the Fischer-Tropsch synthesis: Effects of crystallization time

Yifei Wang, Shouying Huang, Xinsheng Teng, Hongyu Wang, Jian Wang, Qiao Zhao, Yue Wang, Xinbin Ma

期刊论文

Floret-like FeN nanoparticle-embedded porous carbon superstructures from a Fe-covalent triazine polymer

期刊论文

Pd/Fe3O4 supported on bio-waste derived cellulosic-carbon as a nanocatalyst for CC coupling and electrocatalytic

期刊论文

Enhancing the efficiency of nitrogen removing bacterial population to a wide range of C:N ratio (1.5:1 to 14:1) for simultaneous C & N removal

期刊论文

Probing the catalytic activity of M-N

Fan Ge, Qingan Qiao, Xin Chen, You Wu

期刊论文

Fe-Mn-sepiolite as an effective heterogeneous Fenton-like catalyst for the decolorization of reactive

Chengyuan SU,Weiguang LI,Xingzhe LIU,Xiaofei HUANG,Xiaodan YU

期刊论文

Controllable synthesis of a large TS-1 catalyst for clean epoxidation of a C=C double bond under mild

期刊论文

Monte Carlo simulation of the PEMFC catalyst layer

WANG Hongxing, CAO Pengzhen, WANG Yuxin

期刊论文

Mass Transfer-Promoted Fe2+/Fe3+ Circulation Steered by 3D Flow-Through Co-Catalyst System Toward Sustainable

Weiyang Lv,Hao Li,Jinhui Wang,Lixin Wang,Zenglong Wu,Yuge Wang,Wenkai Song,Wenkai Cheng,Yuyuan Yao,

期刊论文

Effect of noble metal nanoparticle size on CN bond cleavage performance in hydrodenitrogenation: a study

期刊论文

Atomistic simulations of plasma catalytic processes

Erik C. Neyts

期刊论文

NO hydrogenation to NH over FeCu/TiO catalyst with improved activity

期刊论文