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Capturing metal clusters at the strong-interaction region to reverse Ostwald ripening

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Science China Materials 2024年第4期67卷 1363-1364页

作者： Shuheng Tian Ding Ma Beijing National Laboratory for Molecular Sciences New Cornerstone Science LaboratoryCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

High-temperature interactions induce sintering of metal nanoparticles(NPs) on heterogeneous catalyst surfaces, leading to reduced surface area and active site loss through Ostwald ripening [1]. This irreversible deactivation necessitates costly catalyst replacement, notably impacting metals like copper in hydrogenation and reforming reactions [2].

关键词： catalyst reforming irreversible

Heterogeneous numerical modelling for the auto thermal reforming of crude glycerol in a fixed bed reactor

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Chinese Journal of Chemical Engineering 2022年第2期35卷 261-268页

作者： Jason Williams Hussameldin Ibrahim Nima Karimi Kelvin Tsun Wai Ng Clean Energy Technologies Research Institute Process Systems EngineeringFaculty of Engineering and Applied ScienceUniversity of ReginaRegina SK S4S 0A2Canada Environmental Systems Engineering Faculty of Engineering and Applied ScienceUniversity of ReginaRegina SK S4S 0A2Canada

A mathematical model for the catalytic autothermal reforming(ATR)reaction of synthetic crude glycerol to hydrogen in a fixed bed tubular reactor(FBTR)and over an in-house developed metal oxide catalyst is presented in this work.The heterogeneous model equations account for a two-phase system of solid catalyst and bulk feed gas.Also,the ATR of crude glycerol reaction scheme and intrinsic kinetic rate model over an active,selective,and stable nickel-based catalyst were integrated in the developed model.Also,the model was validated using experimental data generated in our labs for the ATR of synthetic crude glycerol.The modelling results adequately described the detailed gas product composition and distribution,temperature profiles,and conversion propagation in the axial direction of the fixed bed reactor over a wide range of reaction temperature(773–923 K)and mass-time(12.71–158.23 g cat·min·(mol C)^(-1)).The crude glycerol conversion predicted with the model showing a close resemblance to those obtained experimentally with an average absolute deviation(AAD)of less than 8%.The maximum crude glycerol conversion and hydrogen yield were found to be 92%and 3 mol hydrogen/mol crude glycerol,respectively.Also,the gas product concentration profile in the reactor was adequately described(90%)accuracy with a hydrogen concentration of 39%(volume).

关键词： reforming catalyst fixed

Dry reforming of methane by microsecond pulsed dielectric barrier discharge plasma:Optimizing the reactor structures

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High Voltage 2022年第4期7卷 718-729页

作者： Shuai Zhang Yuan Gao Hao Sun Zhe Fan Tao Shao Beijing International S&T Cooperation Base for Plasma Science and Energy Conversion Institute of Electrical EngineeringChinese Academy of SciencesBeijingChina School of Electronic Electrical and Communication EngineeringUniversity of Chinese Academy of SciencesBeijingChina

Dry reforming of CH4 process can convert greenhouse gases into high-value-added fuels and chemicals with its broad application prospects in environmental protection and renewable energy.Non-thermal plasma is considered an effective alternative method because it can activate CH4 and CO_(2)under low temperature and atmospheric pressure.This paper is aimed to optimize the plasma-assisted dry reforming of CH4 process in a unipolar microsecond pulsed coaxial dielectric barrier discharge by inves-tigating the effects of reactor structures.The results show that the conversions of re-actants and the yields of syngas were significantly affected by the reactor structures.Specifically,a multi-stage or foil external electrode and negative polar discharge could promote CH4 and CO_(2)conversions,gas product yields,and energy conversion efficiencies.For different electrodes,the maximal conversions of CH4 and CO_(2)were 20.4%and 14.1%,with an energy conversion efficiency of 4.4%under our experimental conditions.Higher conversions,yields,and energy conversion efficiencies were obtained with lower power input when applying heat insulation measures.CH4 conversion was promoted to 27.9%with a moderate energy conversion efficiency of 3.8%,but the conversion of CO_(2)was only 12%when packing materials into the reactor.The results can provide specific guidance for designing plasma or plasma-catalytic dry reforming reactor.

关键词： reforming dielectric methane

Recent Development of CO_2 reforming of CH_4 by “Arc” Plasma

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Plasma Science and Technology 2016年第10期18卷 1012-1019页

作者：徐艳张晓晴杨春辉张燕平印永祥 School of Chemistry and Chemical Engineering Xuzhou Institute of Technology Center of Plasma Application School of Chemical EngineeringSichuan University

This paper presents a brief overview of CO2 reforming of CH4 （CRM） by various forms of ＂arc＂ plasma, which is more suitable to CRM, and the energy efficiency is used to evaluate different plasma processes specifically. According to the reported results, the arc thermal plasma with binode exhibited better performance. Moreover, the plasma CRM process was compared with the reported plasma steam reforming of CH4 （SRM） process, and the results showed that the former process has advantages on energy efficiency and CH4 consumption. Additionally, it is believed that the plasma CRM process would be competitive with the conventional SRM process in both energy efficiency and CO2 emission once the heat management is emphasized and the renewable power is used. Finally, a concept of plasma reactor for industrial application is proposed.

关键词： CO2 reforming CH4 plasma energy efficiency

Catalytic performance of perovskite-like oxide doped cerium(La_(2-x)Ce_xCoO_(4±y)) as catalysts for dry reforming of methane

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Chinese Journal of Chemical Engineering 2019年第2期27卷 379-385页

作者： Yukun Bai Yuqi Wang Weijian Yuan Wen Sun Guoxia Zhang Lan Zheng Xiaolong Han Lifa Zhou School of Chemical Engineering Northwest University Shaanxi Provincial Institute of Energy Resources & Chemical Engineering

A series of oxides(La_(2-x)Ce_xCoO_(4±y)) with perovskite-like structure were prepared by the Pechini sol–gel method for dry reforming of methane reaction(DRM). The prepared catalysts were characterized by BET, XRD,TGA, H_2-TPR and SEM. Experimental results indicate that the addition of Ce can impact both sample morphology and catalytic performance significantly compared with La_2CoO_4 catalyst, and LaCeCoO_4 presented the highest catalytic ability among all the samples. The Ce addition tends to increase the specific surface area of La_(2-x)Ce_xCoO_(4±y)from 0.2 to 8.5 m^2·g^(-1), suggesting that LaCeCoO_4 catalyst contained more well-dispersed active sites and more space to reaction. Moreover, the catalytic performance and anti-coking ability were substantially improved after Ce addition during DRM, which may be attributed to the decrease of LaCoO_3 particle size and growth of oxygen storage capacity, respectively.

关键词： Perovskite-like La2-xCexCoO4±y Methane dry reforming Cerium Syngas

Synthesis of Cu/Ni-La_(0.7)Sr_(0.3)Cr_(0.5)Mn_(0.5)O_(3-δ) and its catalytic performance on dry methane reforming

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Journal of Rare Earths 2019年第6期37卷 585-593页

作者： Dingwen Kang Jie Yu Wenhui Ma Min Zheng Yunfei He Pengfei Li Faculty of Metallurgical and Energy Engineering Kunming University of Science and Technology National Engineering Laboratory for Vacuum Metallurgy Kunming University of Science and Technology

In this study,Cu/Ni-La_(0.7)Sr_(0.3)Cr_(0.5)Mn_(0.5)O_(3-δ)(LSCM) catalysts were synthesized via the citric acid-nitrate process(CNP) and chemical co-precipitation. The catalytic performance of Cu/Ni-LSCM catalysts on dry methane reforming was evaluated in a fixed-bed reactor at 550/650 ℃ and atmosphere pressure. Cu/Ni loading was investigated as an influencing factor, which led to 5 cases of samples according to the different Cu/Ni mass ratios. The catalysts were characterized by X-ray diffraction(XRD), field emissionscanning electron microscope(FE-SEM), Brunauer-Emmett-Teller(BET) measurement, X-ray photoelectron spectroscopy(XPS), hydrogen-based temperature-programmed reduction(H_2-TPR) and thermos gravimetric analyzer(TGA). The results show that the methane conversion increases, the resistance against metal sintering increases and the carbon deposition drops after the copper is introduced. This optimum performance can be obtained under Case 3(Cu:Ni:LSCM = 1:3:6 in mass ratio).

关键词： Cu/Ni-LSCM Characterization Dry methane reforming Carbon deposition Rare earths

Ethanol steam reforming study over ZSM-5 supported cobalt versus nickel catalyst for renewable hydrogen generation

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Chinese Journal of Chemical Engineering 2019年第3期27卷 677-684页

作者： Ashutosh Kumar Ram Prasad Yogesh Chandra Sharma Department of Chemistry Indian Institute of Technology (Banaras Hindu University) Varanasi Department of Chemical Engineering & Technology Indian Institute of Technology (Banaras Hindu University) Varanasi

The renewable hydrogen generation through ethanol steam reforming is one of the anticipated areas for sustainable hydrogen generation. To elucidate the role of Ni and Co with ZSM-5 support, catalysts were prepared by wet impregnation method and ethanol steam reforming(ESR) was performed. The catalysts were characterized by HR-XRD, ATR–FTIR, HR-SEM, TEM with SAED, EDAX, surface area analyzer and TPR. It had shown complete ethanol conversion at 773 K, but the selectivity in hydrogen generation was found higher for 10% Ni/ZSM-5 catalyst as compared to 10% Co/ZSM-5. The 10% Ni/ZSM-5 catalyst has about 72% hydrogen selectivity at temperature 873 K. It indicates that Ni is a more sustainable catalyst as compared to Co with ZSM-5 support for ESR. The C_2H_4 was found major undesirable products up to 823 K temperature. Nevertheless, the 10% Ni/ZSM-5 catalyst had shown its stability for high temperature(873 K) ESR performance.

关键词： Ethanol steam reforming Zeolite Hydrogen Renewable energy Catalyst

Reaction parameters influence on the catalytic performance of copper-silica aerogel in the methanol steam reforming

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燃料化学学报 2016年第1期44卷 84-90页

作者： Taher Yousefi Amiri Jafarsadegh Moghaddas Transport Phenomena Research Center Chemical Engineering FacultySahand University of Technology Department of Chemical Engineering Faculty of EngineeringUniversity of Zanjan

Steam reforming of methanol was carried out on the copper-silica aerogel catalyst.The effects of reaction temperature,feed rate,water to methanol molar ratio and carrier gas flowrate on the H_2 production rate and CO selectivity were investigated.M ethanol conversion was increased considerably in the range of about 240-300,after which it increased at a slightly lower rate.The used feed flowrate,steam to methanol molar ratio and carrier gas flowwere 1.2-9.0 m L/h,1.2-5.0 and 20-80 m L/min,respectively.Reducing the feed flowrate increased the H_2 production rate.It was found that an increase in the water to methanol ratio and decreasing the carrier gas flowrate slightly increases the H2production rate.Increasing the water to methanol ratio causes the lowest temperature in which CO formation was observed to rise,so that for the ratio of 5.0 no CO formation was detected in temperatures lower than 375℃.In all conditions,by approaching the complete conversion,increasing the main product concentration,increasing the temperature and contact time,and decreasing the steam to methanol ratio,the CO selectivity was increased.These results suggested that CO was formed as a secondary product through reverse water-gas shift reaction and did not participate in the methanol steam reforming reaction mechanism.

关键词： copper-silica aerogel activity CO selectivity reaction parameters methanol steam reforming

Effect of template on catalytic performance of La_(0.7)Ce_(0.3)Ni_(0.7)Fe_(0.3)O_3 for ethanol steam reforming reaction

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Journal of Rare Earths 2019年第6期37卷 594-601页

作者： Ping Yang Ning Li Junjiang Teng Jian Wu Hao Ma College of Chemical Engineering Guangdong University of Petrochemical Technology College of Chemical Engineering Xiangtan University

Perovskite-type oxides La_(0.7)Ce_(0.3)Ni_(0.7)Fe_(0.3)O_3(LCNF) were synthesized by polystyrene colloidal crystal templating(LCNF-CCT) and polystyrene polymer templating(LCNF-PS) through co-precipitation. The structure and physicochemical properties of the obtained oxides were investigated by scanning electron microscopy, X-ray diffraction, N_2 adsorption-desorption, Fourier transform infrared spectrometry, H_2 temperature-programmed reduction and H_2 temperature-programmed desorption, as well as X-ray photoelectron spectroscopy. The results show that the as-synthesized LCNF-CCT perovskite possesses large specific surface area and regular pore size distribution. In addition, the formation of additional oxygen vacancies on the surface favors the migration of lattice oxygen from the bulk phase to the surface and production of more metallic sites, thus improving the activity and resistance to carbon deposition of catalysts in ethanol steam reforming reaction.

关键词： La0.7Ce0.3Ni0.7Fe0.3O3 Polystyrene colloidal crystal templating Polystyrene polymer templating Ethanol steam reforming Catalytic performance Rare earths