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Journal of Materials Science & Technology 2022年第14期109卷 167-175页

作者： Xiubing Huang Xiaoyu Li Wei Xia Bin Hu martin muhler Baoxiang Peng Beijing Advanced Innovation Center for Materials Genome Engineering Beijing Key Laboratory of Function Materials for Molecule&Structure ConstructionSchool of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 10083China Laboratory of Industrial Chemistry Faculty of Chemistry and BiochemistryRuhr University BochumBochum 44780Germany Max Planck Institute for Chemical Energy Conversion Mülheim a.d.Ruhr 45470Germany

In this work,a novel in situ auto-reduction strategy was developed to encapsulate uniformly dispersed Pd clusters/nanoparticles in MIL-125-NH_(2).It is demonstrated that the amino groups in MIL-125-NH_(2)can react with formaldehyde to form novel reducing groups(-NH-CH_(2)OH),which can in situ auto-reduce the encapsulated Pd^(2+)ions to metallic Pd clusters/nanoparticles.As no additional reductants are required,the strategy limits the aggregation and migration of Pd clusters and the formation of large Pd nanoparticles via controlling the amount of Pd^(2+)precursor.When applied as catalysts in the hydrogenation of phenol in the aqueous phase,the obtained Pd(1.5)/MIL-125-NH-CH_(2)OH catalyst with highly dispersed Pd clusters/nanoparticles with the size of around 2 nm exhibited 100%of phenol conversion and 100%of cyclohexanone selectivity at 70℃ after 5 h,as well as remarkable reusability for at least five cycles due to the large MOF surface area,the highly dispersed Pd clusters/nanoparticles and their excellent stability within the MIL-125-NH-CH_(2)OH framework.

关键词： Pd clusters Pd nanoparticles MIL-125-NH_(2) In situ auto-reduction Double solvent method Hydrogenation of phenol

Nickel nanoparticles supported on nitrogen-doped carbon nanotubes are a highly active,selective and stable CO_(2) methanation catalyst

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Journal of Energy Chemistry 2021年第3期30卷 323-331页

作者： Julian Godde Mariia Merko Wei Xia martin muhler Laboratory of Industrial Chemistry Ruhr University BochumD-44780 BochumGermany

CO_(2) methanation using nickel-based catalysts has attracted large interest as a promising power-to-gas route.Ni nanoparticles supported on nitrogen-doped CNTs with Ni loadings in the range from 10 wt% to 50 wt% were synthesized by impregnation,calcination and reduction and characterized by elemental analysis,X-ray powder diffraction,H_(2) temperature-programmed reduction,CO pulse chemisorption and transmission electron microscopy.The Ni/NCNT catalysts were highly active in CO_(2) methanation at atmospheric pressure,reaching over 50% CO_(2) conversion and over 95% CH_(4) selectivity at 340℃ and a GHSV of50,000 mL g^(-1) h^(-1) under kinetically controlled conditions.The small Ni particle sizes below 10 nm despite the high Ni loading is ascribed to the efficient anchoring on the N-doped CNTs.The optimum loading of 30 wt%-40 wt% Ni was found to result in the highest Ni surface area,the highest degree of conversion and the highest selectivity to methane.A constant TOF of 0.3 s^(-1) was obtained indicating similar catalytic properties of the Ni nanoparticles in the range from 10 wt%to 50 wt% Ni loading.Long-term experiments showed that the Ni/NCNT catalyst with 30 wt% Ni was highly stable for 100 h time on stream.

关键词： CO_(2)methanation Nickel nanoparticles Carbon nanotubes Nitrogen doping

Creation of surface defects on carbon nanofibers by steam treatment

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Journal of Energy Chemistry 2013年第5期22卷 804-810页

作者： Zhengfeng Shao Min Pang Wei Xia martin muhler Changhai Liang Laboratory of Advanced Materials and Catalytic Engineering School of Chemical EngineeringDalian University of Technology Laboratory of Industrial Chemistry Ruhr University Bochum

A direct strategy for the creation of defects on carbon nanofibers (CNFs) has been developed by steam treatment.Nitrogen physisorption,XRD,Raman spectra,SEM and TEM analyses proved the existence of the new defects on CNFs.BET surface area of CNFs after steam treatment was enhanced from 20 to 378 m2/g.Pd catalysts supported on CNFs were also prepared by colloidal deposition method.The different activity of Pd/CNFs catalysts in the partial hydrogenation of phenylacetylene further demonstrated the diverse surfaces of CNFs could be formed by steam treatment.

关键词： carbon nanofibers surface defects steam treatment palladium

A reevaluation of the correlation between the synthesis parameters and structure and properties of nitrogen-doped carbon nanotubes

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Journal of Energy Chemistry 2015年第4期24卷 407-415页

作者： Kunpeng Xie Fengkai Yang Petra Ebbinghaus Andreas Erbe martin muhler Wei Xia Laboratory of Industrial Chemistry Ruhr-University Bochum Max-Planck-Institut für Eisenforschung Gmb H

Nitrogen-doped carbon nanotubes（NCNTs） were synthesized by chemical vapor deposition using cobaltbased oxides as catalyst and ethylenediamine（EDA） as carbon/nitrogen precursor. The influence of growth time,EDA concentration and growth temperature on the morphology,yield,composition,graphitization and oxidation resistance of the NCNTs was systematically investigated by using Raman spectroscopy,temperature-programmed oxidation and other techniques. The NCNT growth from ethylenediamine with a high N/C ratio involves several processes including mainly（1） catalytic growth of NCNTs,（2） homogeneous gas-phase decomposition of EDA,（3） non-catalytic deposition of pyrolytic carbon/nitrogen species and（4）surface etching of amorphous carbon or carbon at defect sites through gasification. At a later growth stage the etching process appears to be dominating,leading to the thinning of nanotubes and the decrease of yield.Moreover,the surface etching through carbon gasification strongly influences the structure and degree of graphitization of NCNTs.

关键词： Carbon nanotubes Nitrogen-doping Catalytic chemical vapor deposition Ethlyenediamine Carbon gasification

Purified oxygenand nitrogen-modified multi-walled carbon nanotubes as metal-free catalysts for selective olefin hydrogenation

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Journal of Energy Chemistry 2013年第2期22卷 312-320页

作者： Peirong Chen Ly May Chew Aleksander Kostka Kunpeng Xie martin muhler Wei Xia Laboratory of Industrial Chemistry Ruhr-University Bochum Department of Microstructure Physics and Alloy Design Max-Planck-Institute for Iron Research

Oxygen and nitrogen-functionalized carbon nanotubes （OCNTs and NCNTs） were applied as metal-free catalysts in selective olefin hydro- genation. A series of NCNTs was synthesized by NH3 post-treatment of OCNTs. Temperature-programmed desorption, N2 physisorption, Raman spectroscopy, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy were employed to characterize the surface properties of OCNTs and NCNTs, aiming at a detailed analysis of the type and amount of oxygen- and nitrogen-containing groups as well as surface defects. The gas-phase treatments applied for oxygen and nitrogen functionalization at elevated temperatures up to 600 ℃ led to the increase of surface defects, but did not cause structural damages in the bulk. NCNTs showed a clearly higher activity than the pristine CNTs and OCNTs in the hydrogenation of 1,5-cyclooctadiene, and also the selectivity to cyclooctene was higher. The favorable catalytic properties are ascribed to the nitrogen-containing surface functional groups as well as surface defects related to nitrogen species. In contrast, oxygen-containing surface groups and the surface defects caused by oxygen species did not show clear contribution to the hydrogenation catalysis.

关键词： multi-walled carbon nanotubes nitrogen-containing functional groups oxygen-containing functional groups metal-free catalyst selectiveolefin hydrogenation

Promoting effect of nitrogen doping on carbon nanotube-supported RuO2 applied in the electrocatalytic oxygen evolution reaction

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Journal of Energy Chemistry 2016年第2期25卷 280-286页

作者： Kunpeng Xie Wei Xia Justus Masa Fengkai Yang Philipp Weide Wolfgang Schuhmann martin muhler Laboratory of Industrial Chemistry Ruhr-University Bochum 44780 Bochum Germany Analytical Chemistry-Center for Electrochemical Sciences (CES) Ruhr-University Bochum 44780 Bochum Germany Competence Centre for Catalysis Chemical Engineering Chalmers University of Technology Gothenburg 41296 Sweden Max Planck Institute for Chemical Energy Conversion 45470 Miilheiman der Ruhr Germany

RuO2 nanoparticles supported on multi-walled carbon nanotubes（CNTs） functionalized with oxygen（OCNTs） and nitrogen（NCNTs） were employed for the oxygen evolution reaction（OER） in 0.1 M KOH.The catalysts were synthesized by metal-organic chemical vapor deposition using ruthenium carbonyl（Ru3（CO）（12）） as Ru precursor. The obtained RuO2/OCNT and RuO2/NCNT composites were characterized using TEM, H2-TPR, XRD and XPS in order probe structure–activity correlations, particularly, the effect of the different surface functional groups on the electrochemical OER performance. The electrocatalytic activity and stability of the catalysts with mean RuO2 particle sizes of 13–14 nm was evaluated by linear sweep voltammetry, cyclic voltammetry, and chronopotentiometry, showing that the generation of nitrogen-containing functional groups on CNTs was beneficial for both OER activity and stability. In the presence of RuO2, carbon corrosion was found to be significantly less severe.

关键词： Ruthenium dioxide Chemical vapor deposition Nitrogen-doped carbon nanotubes Oxygen evolution reaction

Photocatalytic one-step synthesis of Ag nanoparticles without reducing agent and their catalytic redox performance supported on carbon

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Journal of Energy Chemistry 2019年第9期28卷 37-46页

作者： Lingling Shui Guoxiu Zhang Bin Hu Xingxing Chen Mingliang Jin Guofu Zhou Nan Li martin muhler Baoxiang Peng Guangdong Provincial Key Laboratory of Optical Information Materials and Technology&Institute of Electronic Paper Displays South China Academy of Advanced Optoelectronics South China Normal University Guangzhou 510006 Guangdong China Laboratory of Industrial Chemistry Ruhr-University BochumD-44780 Bochum Germany School of Chemical Engineering University of Science and Technology LiaoningAnshan 114051 Liaoning China Shenzhen Guohua Optoelectronics Tech.Co.Ltd Shenzhen 518110 Guangdong China Academy of Shenzhen Guohua Optoelectronics Shenzhen 518110 Guangdong China Max Planck Institute for Chemical Energy Conversion D-45470 Miilheim an der Ruhr Germany

Synthesis of silver nanoparticles(Ag NPs) with state-of-the-art chemical or photo-reduction methods generally takes several steps and requires both reducing agents and stabilizers to obtain NPs with narrow size distribution.Herein, we report a novel method to synthesize Ag NPs rapidly in one step, achieving typical particle sizes in the range from 5 to 15 nm.The synthesis steps only involve three chemicals without any reducing agent: AgNO3 as precursor, polyvinylpyrrolidone(PVP) as stabilizer, and AgCl as photocatalyst.The Ag NPs were supported on carbon and showed excellent performance in thermal catalytic pnitrophenol reduction and nitrobenzene hydrogenation, and as electrocatalyst for the oxygen reduction reaction.

关键词： Silver Carbon Photoreduction Hydrogenation Oxygen reduction reaction

State-of-the-art progress in the selective photo-oxidation of alcohols

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Journal of Energy Chemistry 2021年第11期30卷 338-350,I0007页

作者： Zewen Shen Yezi Hu Bingfeng Li Yingtong Zou Shaojun Li GWilma Busser Xiangke Wang Guixia Zhao martin muhler College of Environmental Science and Engineering North China Electric Power UniversityBeijing 102206China Laboratory of Industrial Chemistry Faculty of Chemistry and BiochemistryRuhr-Universität BochumUniversitätsstrasse150D-44780 BochumGermany

Photocatalytic oxidation of alcohols has received more and more attention in recent years following the numerous studies on the degradation of pollutants, hydrogen evolution, and CO_(2) reduction by photocatalysis. Instead of the total oxidation of organics in the degradation process, the photo-oxidation of alcohols aims at the selective conversion of alcohols to produce carbonyl/acid compounds. Promising results have been achieved in designing the catalysts and reaction system, as well as in the mechanistic investigations in the past few years. This review summarizes the state-of-the-art progress in the photo-oxidation of alcohols, including the development of photocatalysts and cocatalysts, reaction conditions including the solvent and the atmosphere, and the exploration of mechanisms with scavengers experiment, electron paramagnetic resonance (EPR) and diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. The challenges and outlook for the further research in this field are also discussed.

关键词： Alcohol oxidation Photocatalysis Carbonyl compounds Selectivity

Effects of Potassium and Manganese Promoters on Nitrogen-Doped Carbon Nanotube-Supported Iron Catalysts for CO_2 Hydrogenation

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Engineering 2017年第3期3卷 385-392页

作者： Praewpilin Kangvansura Ly May Chew Chanapa Kongmark Phatchada Santawaja Holger Ruland Wei Xia Hans Schulz Attera Worayingyong martin muhler Sciennfic Equipment Center Faculty of Science Kasetsart University Bangkok 10900 Thailand Laboratory of Industrial Chemistry Ruhr-University Bochum Bochum 44780. Germany Department of Materials Science Faculty of Science Kasetsart University Bangkok 10900 Thailand Department of Chemistry Faculty of Science Kasetsart University Bangkok 10900 Thailand Engler-Bunte-lnstitute Karlsruhe Institute of Technology Karlsruhe 76131 Germany

氮掺杂碳纳米管(NCNTs)作为载体负载铁(Fe)纳米颗粒,可应用于CO_2多相催化加氢反应(633 K和25 bar)。当将钾(K)和锰(Mn)作为助催化剂时,Fe/NCNT展现出优异的CO_2加氢性能,在体积空速(GHSV)为3.1 L·g^(–1)·h^(–1)时转化率可达34.9%... 详细信息

氮掺杂碳纳米管(NCNTs)作为载体负载铁(Fe)纳米颗粒,可应用于CO_2多相催化加氢反应(633 K和25 bar)。当将钾(K)和锰(Mn)作为助催化剂时,Fe/NCNT展现出优异的CO_2加氢性能,在体积空速(GHSV)为3.1 L·g^(–1)·h^(–1)时转化率可达34.9%。当使用K作为助催化剂时,反应对烯烃和短链烷烃具有高的选择性。当K和Mn同时作为助催化剂时,其催化活性能够稳定地维持60 h。助催化剂Mn的结构效应通过X射线衍射、氢气程序升温还原以及近边X射线吸收精细结构进行表征。助催化剂Mn不仅能够稳定中间态FeO,且能降低程序升温还原的起始温度。通过探针反应NH3的催化分解来表征助催化剂效应。当K和Mn作为助催化剂时,Fe/NCNT具有最好的催化活性。在还原条件下,当K作为助催化剂时,Fe/NCNT具有最优异的热稳定性。

关键词： CO_2加氢铁基催化剂 n型碳纳米管 Mn助剂 K助剂

水滑石基钴铜催化剂中钴的碳化在高碳醇合成中的作用

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Chinese Journal of Catalysis 2019年第11期40卷 1731-1740页

作者： Janine Nebel Stefan Schmidt Qiushi Pan Katrin Lotz Stefan Kaluza martin muhler 波鸿鲁尔大学工业化学实验室德国波鸿44780 弗劳恩霍夫环境安全与能源技术研究所德国奥伯豪森46047

Co-Cu基催化剂广泛用于合成气制高碳醇反应(HAS)中.尽管很难从本质上完全理解催化剂的活性位,但是在HAS条件下生成的Co2C对反应的贡献是显而易见的.开发了CO预处理工艺,系统地研究了钴的碳化对催化剂结构性能和催化性能的影响.通过在HA... 详细信息

Co-Cu基催化剂广泛用于合成气制高碳醇反应(HAS)中.尽管很难从本质上完全理解催化剂的活性位,但是在HAS条件下生成的Co2C对反应的贡献是显而易见的.开发了CO预处理工艺,系统地研究了钴的碳化对催化剂结构性能和催化性能的影响.通过在HAS反应之前将催化剂暴露在含CO的气氛中,催化剂表面发生Co的富集,然后形成碳化物.这种表面改性减少了烃类的形成,促进了C2+OH的形成.催化剂经20 bar下CO预处理后,乙醇选择性最高,烃类选择性最低.

关键词：高碳醇合成 Co-Cu催化剂碳化钴 CO预处理