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Catalytic methane removal to mitigate its environmental effect

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中国科学：化学英文版 2023年第4期66卷 1032-1051页

作者： Chao Wang Youxun Xu junwang tang Department of Chemical Engineering University College LondonLondon WCIE 7JEUK

Large reserve of methane,in the form of natural gas and methane hydrate,has been discovered and it has been intensively used as a fuel,or as a building block for the chemical synthesis.However,severe environmental and climatic issues caused by the leakage of methane during the production,transportation and use of methane are overlooked.This offers incentives for the catalytic removal of methane.Nevertheless,due to the inert nature of methane molecules,the activation of methane via thermocatalysis requires harsh reaction conditions.The high reaction temperature not only increases the capital cost but also accelerates the deactivation of catalysts due to sintering and/or coking.The development of robust and stable catalysts with a low operating temperature has become the focus of the research on thermocatalytic methane oxidation.Photocatalysis,which uses the energy of photons instead of heat to drive chemical reactions under ambient conditions,offers another approach to methane removal.This review will cover the development of high-efficiency catalysts for methane combustion in both thermo-and photocatalysis.Moreover,the fundamental understanding of the active sites,surface chemistry and reaction pathway will also be discussed.Finally,the challenges facing in the catalytic removal of methane will be summarized and potential solutions will be provided.This review will be of interest to researchers in the field of heterogeneous catalysis,materials design,and chemical engineering.

关键词： methane oxidation environmental remediation thermocatalysis photocatalysis fundamental understandings

Insights on Carbon Neutrality by Photocatalytic Conversion of Small Molecules into Value-Added Chemicals or Fuels

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Accounts of Materials Research 2022年第12期3卷 1206-1219页

作者： Haimiao Jiao Chao Wang Lunqiao Xiong junwang tang Department of Chemical Engineering University College London

CONSPECTUS:Photocatalytic conversion of small molecules(including H_(2)O,CO_(2),N_(2),CH4,and benzene)into value-added chemicals or fuels(e.g.,H_(2),NH_(3),C_(2)+,etc.)is a promising strategy to cope with both the worldwide increasing energy demand and greenhouse gas emission in both energy sectors and chemical industry,thus paving an effective way to carbon neutrality.On the other hand,compared with conventionally thermo-or electrocatalytic processes,photoactivation can convert these very stable small molecules by the unexhausted solar energy,so leading to store solar energy in chemical bonds.Thus,it can effectively reduce the reliance on the nonrenewable fossil fuels and avoid the substantial emission of hazardous gases such as CO_(2),NOx,and so on while producing valued-added chemicals.For example,semiconductors can absorb solar light to split H_(2)O into H2 and O2 or convert CO_(2)to alcohols,which can then be used as zero or neutral carbon energy sources.

关键词： neutral convert bonds

Microwave Catalytic Depolymerization of Polyethylene Terephthalate Plastic to the Monomers

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CCS Chemistry 2023年第12期5卷 2818-2831页

作者： Zhe Yuan Jianlong Yang George Manos junwang tang Department of Chemical Engineering University College LondonLondon WC1E 7JE(United Kingdom) Key Lab of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education The Energy and Catalysis HubCollege of Chemistry and Materials ScienceNorthwest UniversityXi’an Industrial Catalysis Center Department of Chemical EngineeringTsinghua UniversityBeijing

Plastic waste management has emerged as a critical environmental issue due to the exponential increase in plastic consumption worldwide.Polyethylene terephthalate(PET)is extensively used in the production of water bottles,which constitutes a significant fraction of the plastic waste.PET recycling is a challenging task due to the lack of efficient and cost-effective depolymerization methods.In this study,we developed a microwave(MW)catalytic depolymerization method for PET recycling using modified zinc oxide loaded with manganese oxide as a cocatalyst.The modified Mn_(3)O_(4)/ZnO catalyst presents high efficiency in depolymerizing PET into its monomers with only 0.4 wt% ratio of the catalyst to PET at 175℃ for 5 min,resulting in 100% conversion of PET and 88% selectivity toward bis-hydroxyethyl terephthalate monomers.It is believed that Mn_(3)O_(4)provides additional Lewis acid sites,promoting the dissociation of glycol from PET,and the MW irradiation plays a crucial role in rapidly heating the ethylene glycol and the catalyst,thereby accelerating the PET depolymerization process.In addition,the heterogeneous nature of the catalyst facilitates its easy separation from the reaction mixture for reuse,simplifying the catalyst recovery process and enabling costeffective and sustainable PET recycling.Thus,this study provides an innovative and sustainable solution for PET recycling,contributing toward the circular economy and mitigating the environmental impact of plastic waste.

关键词： polyethylene terephthalate plastic recycling microwave catalysis depolymerization bishydroxyethyl terephthalate monomers

Strategies and reaction systems for solardriven CO_(2) reduction by water

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碳中和(英文)

碳中和(英文) 2022年第1期1卷 578-597页

作者： Ji Bian Ziqing Zhang Ye Liu Enqi Chen junwang tang Liqiang Jing Department Key Laboratory of Functional Inorganic Materials Chemistry(Ministry of Education) International Joint Research Center and Lab for Catalytic TechnologySchool of Chemistry and Materials ScienceHeilongjiang UniversityHarbin 150080People’s Republic of China Department of Chemical Engineering University College London Torrington PlaceWC1E 7JELondonUK

Solar driven CO_(2) conversion into high-value-added chemicals and energy-rich fuels is one of the promising strategies to tackle global warming and to address the energy-supply crisis.Even though enormous effort has been devoted to exploring all sorts of homogeneous and heterogeneous photocatalysts,the current efficiency and more importantly selectivity to valuable chemicals are still rather moderate,thus it is desired to develop high-efficiency photocatalytic system toward CO_(2) reduction with excellent selectivity.In this review,fundamental aspects of photocatalytic CO_(2) reduction by pure water,the reaction systems and the reliable method for detection of the products are firstly described.Thereafter the recent advances of the main strategy for improving the photocatalytic CO_(2) reduction from the perspective of promoting the CO_(2) adsorption and activation,accelerating the kinetics of water oxidation,and modulating charge separation are overviewed.The prospects and challenges on precise designing heterogeneous catalysts for CO_(2) photoreduction are proposed at the end,indicating the significance for the further development of photocatalytic systems with high CO_(2) conversion efficiency and product selectivity.

关键词： Photocatalysis CO_(2)reduction Selectivity Water Solar fuel production

Surface chemistry connecting heterogeneous catalysis, photocatalysis and plasmonic catalysis

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Chinese Chemical Letters 2018年第6期29卷 725-726页

作者： Weixin Huang Zili Wu junwang tang Wei David Wei Xuefeng Guo Hefei National Laboratory for Physical Sciences at the Microscale CAS Key Laboratory of Materials for Energy Conversion and Department of Chemical Physics University of Science and Technology of China Chemical Science Division and Center for Nanophase Materials Sciences Oak Ridge National Laboratory Department of Chemical Engineering University College London Department of Chemistry University of Florida College of Chemistry and Chemical Engineering Nanjing University

Chemical reactions catalyzed by solid catalysts have recently expanded rapidly from traditional heterogeneous catalytic reactions to photocatalytic reactions and further to plasmonic-catalytic reactions, however, the fundamental understanding of the commonalities and differences among heterogeneous catalysis, photocatalysis and plasmonic catalysis is not well established. Adsorption/reactions/desorption on solid catalyst surfaces commonly occur during these catalytic processes, thus surface chemistry of solid catalysts can be taken to bridge the fundamental understanding among heterogeneous catalysis, photocatalysis and plasmonic catalysis.

关键词： Ti photocatalysis and plasmonic catalysis

BiVO_4 semiconductor sensitized solar cells

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Science China Chemistry 2015年第9期58卷 1489-1493页

作者： Yi Li Jun Zhu Hui Chu Junfeng Wei Feng Liu Mei Lv junwang tang Bing Zhang Jianxi Yao Zhipeng Huo Linhua Hu Songyuan Dai CAS Key Laboratory of Novel Thin Film Solar Cells Institute of Applied Technology Hefei Institutes of Physical Science Chinese Academy of Sciences Department of Modern Physics University of Science and Technology of China Department of Chemical Engineering University College London State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing Key Lab of Novel Thin Film Solar Cells

Semiconductor sensitized solar cells(SSSCs) are promising candidates for the third generation of cost-effective photovoltaic solar cells and it is important to develop a group of robust, environment-friendly and visible-light-responsive semiconductor sensitizers. In this paper, we first synthesized bismuth vanadate(Bi VO4) quantum dots by employing facile successive ionic layer adsorption and reaction(SILAR) deposition technique, which we then used as a sensitizer for solar energy conversion. The preliminary optimised oxide SSSC showed an efficiency of 0.36%, nearly 2 orders of magnitude enhancement compared with bare Ti O2, due to the narrow bandgap absorption of Bi VO4 quantum dots and intimate contact with the oxide substrate. This result not only demonstrates a simple method to prepare Bi VO4 quantum dots based solar cells, but also provides important insights into the low bandgap oxide SSSCs.

关键词：太阳能电池敏化剂半导体可见光响应量子点氧化物成本效益沉积技术

“实验动物学”教学改革与实践--基于疾病动物模型构建的综合创新实验教学

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科教导刊 2024年第10期 93-95页

作者：张扬唐军旺骆薇辜澜涛深圳市坪山区人民医院广东深圳518083 南方医科大学坪山总医院广东深圳518083 桂林医学院广西桂林541199

“实验动物学”是一门重要的基础课程,在医科院校普遍开展,其实践性和应用性兼具,主要培养学生的创新思维和实践能力。当前“实验动物学”实验课多采用验证性、重复性实验,难以达到培养复合型和创新型人才的目的。文章基于疾病动物模型... 详细信息

“实验动物学”是一门重要的基础课程,在医科院校普遍开展,其实践性和应用性兼具,主要培养学生的创新思维和实践能力。当前“实验动物学”实验课多采用验证性、重复性实验,难以达到培养复合型和创新型人才的目的。文章基于疾病动物模型构建的综合创新实验教学设计,探讨其具体实践及应用效果,以期为广大高校开展实验动物学实验课程改革提供借鉴和启发。

关键词：实验动物学疾病动物模型教学改革

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Author Spotlight

CCS Chemistry 2023年第12期5卷 2679-2684页

作者： tang, junwang (John) Stuparu, Mihaiela C. Tian, Tian Xu, Jingsan Liu, Yanlan Acad Europe London England Tsinghua Univ Mat Chem & Catalysis Beijing Peoples R China UCL London England Nanyang Technol Univ Sch Chem Chem Engn & Biotechnol Singapore Singapore Wuhan Univ Coll Chem Wuhan Peoples R China Queensland Univ Technol Brisbane Australia Hunan Univ Mol Sci & Biomed Lab MBL State Key Lab Chemo Biosensing & Chemometr Changsha Peoples R China Hunan Univ Coll Chem & Chem Engn Changsha Peoples R China

junwang(John)tang(唐军旺).Prof.junwang(John)tang obtained his Ph.D.in physical chemistry from the Dalian Institute of Chemical Physics(DICP),Chinese Academy of Sciences,in 2001.He is currently a Member of the Academy of Europe,a Fellow of the European Academy of Sciences,a Fellow of the Royal Society of Chemistry(RSC),and a Fellow of the Institute of Materials,Minerals,and Mining(FIMMM).

关键词： Fellow Dalian currently

双反应位点共修饰WO_(3)光催化活化甲烷

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Chinese Journal of Catalysis 2023年第3期46卷 103-112页

作者：王珂然罗磊王超唐军旺西北大学化学与材料科学学院能源与催化中心合成天然功能分子化学教育部重点实验室陕西西安710127 伦敦大学学院化学工程系英国伦敦

在温和条件下将CH_(4)转化为液态含氧化合物,对解决能源和环境问题,实现可持续发展具有重要意义.光催化CH_(4)转化技术可利用光能驱动载流子分离,实现温和条件下CH_(4)直接转化.然而,该过程面临着活性低和选择性差的瓶颈问题.WO_(3)作... 详细信息

在温和条件下将CH_(4)转化为液态含氧化合物,对解决能源和环境问题,实现可持续发展具有重要意义.光催化CH_(4)转化技术可利用光能驱动载流子分离,实现温和条件下CH_(4)直接转化.然而,该过程面临着活性低和选择性差的瓶颈问题.WO_(3)作为常见的光催化剂之一,具有热稳定好、可见光响应性能好和价带空穴氧化能力强等特性,但存在光生电荷容易复合的问题.助催化剂能够发挥促进光生电荷分离和加速表面催化反应的双重作用,有助于局域电子密度的重新分布,从而促进光生电荷的分离和转移.然而,单一助催化剂促进光生电荷分离具有一定局限性,为了进一步加强光生电荷的分离和转移,引入氧空位(OVs)是个很好的选择, OVs不仅可通过插入杂质能级增强光吸收和促进电荷分离,而且可以促进小分子吸附和活化,进而加速表面反应动力学.本文采用双活性位点Pd纳米颗粒和OVs改性的WO_(3)为催化剂,实现温和条件下CH_(4)转化为液体含氧化合物.参照文献(J. Am. Chem. Soc., 2017, 139, 4486-4492)报道,采用水热法合成了Pd纳米颗粒和OVs共改性的Pdx-def-WO_(3)光催化剂.电子顺磁共振波谱(EPR)、X射线光电子能谱(XPS)和透射电镜(TEM)等表征结果表明, OVs和Pd成功修饰在WO_(3)基底上.光催化CH_(4)转化反应结果表明,与WO_(3)相比,优化的Pd_(0.5)-def-WO_(3)光催化剂使C1含氧化合物产量提高近33倍,产率为7018 μmol·g^(-1)·h^(-1),对初级产物(CH_(3)OH和CH_(3)OOH)的选择性高达81%.稳态荧光光谱和电化学测试实验表明Pd_(0.5)-def-WO_(3)催化剂的光生电荷的分离能力最强.原位光照XPS谱表明Pd3d结合能在光照下向高结合能方向移动,证明了Pd纳米粒子是光生空穴受体.原位光照EPR结果表明,光照下OVs信号的增强,证明了OVs作为光生电子受体.因此, Pd和OVs协同促进光生电荷分离,实现CH_(4)高活性和高选择性转化.同位素实验表明, O_(2)是液态含氧化合物的主要氧源, H_(2)O的作用主要是通过产生羟基自由基(·OH)促进CH_(4)的活化.因此,在H_(2)O的辅助下, Pd纳米颗粒和OVs双反应位点共修饰的WO_(3)光催化剂实现了CH_(4)在室温下被O_(2)选择性氧化为液态含氧化合物.综上,本工作为CH_(4)选择性氧化反应的活性和选择性调控提供了深入的理解.

关键词：光催化甲烷转化助催化剂氧化钨氧空位