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绿色银纳粒子的共振散射光谱研究 被引量:25
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作者 蒋治良 钟福新 《化学学报》 SCIE CAS CSCD 北大核心 2001年第3期438-441,共4页
以柠檬钠作还原剂,采用紫外光-可见光二步光化学法制备了绿色银纳米粒子,在399.4nm,470nm和520nm处有三个共振散射峰。从超分子和纳米粒子这一整体出发,探讨了共振散射光谱产生的原因及银超分子光反应机理。
关键词 绿色银纳米粒子 共振散射光谱 银超分子 光反应机理 光化学法 合成
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Mass Spectrometry Study of OH-initiated Photooxidation of Toluene 被引量:1
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作者 黄明强 张为俊 +5 位作者 王振亚 方黎 孔蕊弘 单晓斌 刘付轶 盛六四 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2011年第6期672-678,I0003,共8页
The composition of products formed from photooxidation of the aromatic hydrocarbon toluene was investigated. The OH-initiated photooxidation experiments were conducted by irradiating toluene/CH3ONO/NO/air mixtures in ... The composition of products formed from photooxidation of the aromatic hydrocarbon toluene was investigated. The OH-initiated photooxidation experiments were conducted by irradiating toluene/CH3ONO/NO/air mixtures in a smog chamber, the gaseous products were detected under the supersonic beam conditions by utilizing vacuum ultraviolet photoionization mass spectrometer using synchrotron radiation in real-time. And an aerosol time-of-flight mass spectrometer was used to provide on-line measurements of the individual secondary organic aerosol particle resulting from irradiating toluene. The experimental results demonstrated that there were some differences between the gaseous products and that of particle-phase, the products of glyoxal, 2-hydroxyl-3-oxo-butanal, nitrotoluene, and methyl-nitrophenol only existed in the particle-phase. However, furane, methylglyoxal, 2-methylfurane, benzaldehyde, cresol, and benzoic acid were the predominant photooxidation products in both the gas phase and particle phase. 展开更多
关键词 TOLUENE Secondary organic aerosol Smog chamber Desorption/ionization Reaction mechanism
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Revealing the unexpected promotion effect of EuO_x on Pt/CeO_2 catalysts for catalytic combustion of toluene 被引量:8
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作者 Baoming Zhao Yanfei Jian +1 位作者 Zeyu Jiang Chi He 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第4期543-552,M0003,共11页
Pt/Eu2O3-CeO2 materials with different Eu concentrations were prepared and applied to toluene destruction,and the remarkable promotion impact of EuOx on Pt/CeO2 can be observed.The characterization results reveal that... Pt/Eu2O3-CeO2 materials with different Eu concentrations were prepared and applied to toluene destruction,and the remarkable promotion impact of EuOx on Pt/CeO2 can be observed.The characterization results reveal that the presence of EuOx significantly enhances the redox property,lattice O concentration,and Ce3+ ratio of the Pt/CeO2 material,which facilitates the dispersion and activity of Pt active sites and thus accelerates the decomposition process of toluene.Among all catalysts,a sample with an Eu content of 2.5 at.%(Pt/EC-2.5)possesses the best catalytic activity with 0.09 vol% of toluene completely destructed at 200 ℃ under a relatively high GHSV of 50000 h^-1.The possible reaction pathway and mechanism of toluene combustion over Pt/Eu2O3-CeO2 samples are presented according to in-situ DRIFTS,which confirms that the toluene oxidation process obeys the Mars-van Krevelen mechanism with aldehydes and ketones as primary organic intermediates. 展开更多
关键词 Pt/Eu2O3-CeO2 material Promotion effect TOLUENE Catalytic oxidation In-situ DRIFTS Reaction mechanism
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Light-Induced Reaction of Benzene with Carbonates
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作者 姬铭松 董春华 +1 位作者 张华烨 杨新征 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2016年第3期319-324,I0001,共7页
We found an ultraviolet (UV)-light induced formation of biphenyl and sodium benzoate from benzene and sodium carbonate. The reaction happens in the interface of benzene and aqueous solution at the room temperature. ... We found an ultraviolet (UV)-light induced formation of biphenyl and sodium benzoate from benzene and sodium carbonate. The reaction happens in the interface of benzene and aqueous solution at the room temperature. After 5 h of UV-light exposure, 11.4% of initial amount of 4.4 g (5.0 mL) benzene are converted to biphenyl and sodium benzoate, which are distributed in benzene and aqueous solution, respectively. Using density function theory (DFT) and time dependent DFT, we have investigated the mechanism of this light-induced reaction, and found that the sodium carbonate is not only a reactant for the formation of sodium benzoate, but also a catalyst for the formation of biphenyl. 展开更多
关键词 BENZENE CARBONATES Light-induced reaction Density function theory calcu-lation MECHANISM
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The pivotal effects of oxygen vacancy on Bi_2MoO_6:Promoted visible light photocatalytic activity and reaction mechanism 被引量:11
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作者 Yanjuan Sun Hong Wang +4 位作者 Qian Xing Wen Cui Jieyuan Li Sujuan Wu Lidong Sun 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第5期647-655,共9页
Bi2MoO6,a typical Bi-based photocatalyst,has received increasing interests and been widely applied in various fields.However,the visible light photocatalytic activity of Bi2MoO6 is still restricted by some obstacles,s... Bi2MoO6,a typical Bi-based photocatalyst,has received increasing interests and been widely applied in various fields.However,the visible light photocatalytic activity of Bi2MoO6 is still restricted by some obstacles,such as limited photo-response and low charge separation efficiency.In this work,we developed a facile method to introduce artificial oxygen vacancy into Bi2MoO6 microspheres,which could effectively address these problems and realize highly efficient visible light photocatalysis.The experimental and theoretical methods were combined to explore the effects of oxygen vacancy on the electronic structure,photocatalytic activity and the reaction mechanism toward NO removal.The results showed that the addition of NaBH4 during catalyst preparation induced the formation of oxygen vacancy in Bi2MoO6,which plays a significant role in extending the visible light absorption of Bi2MoO6.The visible light photocatalytic activity of Bi2MoO6 with oxygen vacancy was obviously enhanced with a NO removal ratio of 43.5%,in contrast to that of 25.0%with the pristine Bi2MoO6.This can be attributed to the oxygen vacancy that creates a defect energy level in the band gap of Bi2MoO6,thus facilitating the charge separation and transfer processes.Hence,more reactive radicals were generated and participated in the photocatalytic NO oxidation reaction.The in situ FT-IR was used to dynamically monitor the photocatalytic NO oxidation process.The reaction intermediates were observed and the adsorption-reaction mechanism was proposed.It was found that the reaction mechanism was unchanged by introducing the oxygen vacancy in Bi2MoO6.This work could provide new insights into the understanding of the oxygen vacancy in photocatalysis and gas-phase photocatalytic reaction mechanism. 展开更多
关键词 Oxygen vacancy PHOTOCATALYSIS Reaction mechanism In situ FT-IR NO removal
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Facile fabrication and enhanced photocatalytic performance of visible light responsive UiO-66-NH2/Ag2CO3 composite 被引量:11
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作者 Yun-Cai Zhou Xue-Yan Xu +3 位作者 Peng Wang Huifen Fu Chen Zhao Chong-Chen Wang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第12期1912-1923,共12页
A series of UiO-66-NH2/Ag2CO3 Z-scheme heterojunctions were prepared by a simple ion-exchange-solution method using UiO-66-NH2 and semiconductor Ag2CO3 as precursors.The photocatalytic activities of UAC-X(UAC-20,50,10... A series of UiO-66-NH2/Ag2CO3 Z-scheme heterojunctions were prepared by a simple ion-exchange-solution method using UiO-66-NH2 and semiconductor Ag2CO3 as precursors.The photocatalytic activities of UAC-X(UAC-20,50,100,150,200)Z-scheme heterojunctions toward the hexavalent chromium(Cr(VI))reduction and UAC-100 toward oxidative degradation of four organic dyes like rhodamine B(RhB),methyl orange(MO),congo red(CR),and methylene blue(MB)under visible light irradiation were investigated.The effects of different pH(pH=2,3,4,6,8),small organic acids(citric acid,tartaric acid,and oxalic acid),and foreign ions(ions in tap water and surface water)on Cr(VI)reduction were explored.The results revealed that the UAC-100 heterojunctions displayed more remarkable Cr(VI)reduction performance than the pristine UiO-66-NH2 and Ag2CO3,resulting from the improved separation of photo-induced electrons and holes.The enhanced photocatalytic activity of UAC-100 was further confirmed by the photoluminescence measurement,electrochemical analysis,and active species trapping experiments.After four cycles’experiments,the photocatalytic Cr(VI)reduction efficiency over UAC-100 was still over 99%,which exhibited that UAC-100 had excellent reusability and stability.Finally,the corresponding photocatalytic reaction mechanism was proposed and tested. 展开更多
关键词 Metal-organic framework Ag2CO3 Hexavalent chromium PHOTOCATALYTIC Reaction mechanism
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Bi quantum dots implanted 2D C-doped BiOCl nanosheets: Enhanced visible light photocatalysis efficiency and reaction pathway 被引量:7
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作者 Ye He Jieyuan Li +6 位作者 Kanglu Li Minglu Sun Chaowei Yuan Ruimin Chen Jianping Sheng Geng Leng Fan Dong 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2020年第9期1430-1438,共9页
The simultaneous integration of heteroatom doping and surface plasmon resonance(SPR) modulation on semiconductor photocatalysts could be capable of improving visible light utilization and charge separation, achieving ... The simultaneous integration of heteroatom doping and surface plasmon resonance(SPR) modulation on semiconductor photocatalysts could be capable of improving visible light utilization and charge separation, achieving better solar light conversion and photocatalysis efficiency. For this purpose, we have designed a novel Bi quantum dots(QDs) implanted C-doped BiOCl photocatalyst(C/BOC/B) for NOx removal. The feasibility was firstly evaluated through density functional theory(DFT) calculations methods, which indicates that the enhanced photocatalytic performance could be expected owing to the synergistic effects of doped C heteroatoms and loaded Bi QDs. Then, the C/BOC/B was synthesized via a facile hydrothermal method and exhibited efficient and stable visible light photocatalytic NO removal. The results found that the doped C atoms can serve as electron guides to induce oriented charge transfer from Bi QDs to BiOCl, while the Bi QDs can act as light-capture and electron-donating sites. The reaction pathway and mechanism for NO conversion was unveiled by in situ Fourier-transform infrared spectroscopy combined with DFT calculation. The enhanced adsorption of reactants and intermediates could promote the overall reaction efficiency and selectivity in photocatalytic NO conversion. This work could provide a new perspective on the mechanistic understanding of the synergistic effects toward non-metal doping and SPR effects in semiconductor photocatalysts, and this presented technique could be extended for other semiconductor materials. 展开更多
关键词 BiOCl Carbon doping Bi quantum dot PHOTOCATALYSIS Reaction mechanism
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SrTiO3/BiOI heterostructure: Interfacial charge separation, enhanced photocatalytic activity, and reaction mechanism 被引量:5
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作者 Ruimin Chen Hong Wang +4 位作者 Huizhong Wu Jianping Sheng Jieyuan Li Wen Cui Fan Dong 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2020年第4期710-718,共9页
Heterostructured photocatalysts provide an effective way to achieve enhanced photocatalytic performances through efficient charge separation.Although both wide-and narrow-band-gap photocatalysts have been widely inves... Heterostructured photocatalysts provide an effective way to achieve enhanced photocatalytic performances through efficient charge separation.Although both wide-and narrow-band-gap photocatalysts have been widely investigated,the charge separation and transfer mechanism at the contacting interface of the two has not been fully revealed.Here,a novel SrTiO3/BiOI(STB)heterostructured photocatalyst was successfully fabricated by using a facile method.The heterostructure in the photocatalyst extends the photoabsorption to the visible light range,and thus,high photocatalytic NO removal performance can be achieved under visible light irradiation.A combination of experimental and theoretical evidences indicated that the photogenerated electrons from the BiOI semiconductor can directly transfer to the SrTiO3 surface through a preformed electron delivery channel.Enhanced electron transfer was expected between the SrTiO3 and BiOI surfaces under light irradiation,and leads to efficient ROS generation and thus a high NO conversion rate.Moreover,in situ diffused reflectance infrared Fourier transform spectroscopy revealed that STB can better inhibit the accumulation of the toxic intermediate NO2 and catalyze the NO oxidation more effectively.This work presents a new insight into the mechanism of the interfacial charge separation in heterostructures and provides a simple strategy to promote the photocatalytic technology for efficient and safe air purification. 展开更多
关键词 HETEROSTRUCTURE SrTiO3/BiOI Charge separation PHOTOCATALYSIS Reaction mechanism
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Bio‐inspired nanostructured g-C_(3)N_(4)-based photocatalysts:A comprehensive review 被引量:5
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作者 Bo Lin Mengyang Xia +3 位作者 Baorong Xu Ben Chong Zihao Chen Guidong Yang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2022年第8期2141-2172,共32页
As a new organic conjugated semiconductor,graphitic carbon nitride(g-C_(3)N_(4))is emerging as a fascinating material for various photocatalytic applications due to its adjustable electronic structure,outstanding ther... As a new organic conjugated semiconductor,graphitic carbon nitride(g-C_(3)N_(4))is emerging as a fascinating material for various photocatalytic applications due to its adjustable electronic structure,outstanding thermal endurance,appealing chemical stability,low cost,and environmental friendliness.Nevertheless,unmodified bulk g-C_(3)N_(4) possesses some intrinsic limitations related to poor crystallinity,marginal visible-light harvesting,easy recombination of charge pairs,small surface area,and slow charge migration,which give rise to the low quantum efficiency of photocatalytic reactions.One efficient strategy to overcome these shortcomings is the manipulation of the microstructures of g-C_(3)N_(4).Other than the traditional structure control,mimicking the structures of creatures in nature to design and construct bio-inspired structures is a promising approach to improve the photocatalytic performance of g-C_(3)N_(4) and even g-C_(3)N_(4)-based systems.This review summarizes the recent advances of the traditional structure-control of g-C_(3)N_(4)-based systems,and bio-inspired synthesis of g-C_(3)N_(4)-based systems from two aspects of structural bionics and functional bionics.Furthermore,the fundamentals of bio-inspired design and fabrication of g-C_(3)N_(4)-based systems are introduced in detail.Additionally,the different theoretical calculations,diverse photocatalytic applications and various modification strategies of bio-inspired structured g-C_(3)N_(4)-based systems are recapped.We believe that this work will be a guiding star for future research in the new field of biomimetic photocatalysis. 展开更多
关键词 g-C_(3)N_(4)-based system Bio-inspired design Structure control Biomimetic photocatalysis Reaction mechanism
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Pivotal roles of artificial oxygen vacancies in enhancing photocatalytic activity and selectivity on Bi_2O_2CO_3 nanosheets 被引量:6
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作者 Hongjing Liu Peng Chen +4 位作者 Xiaoya Yuan Yuxin Zhang Hongwei Huang Li’ao Wang Fan Dong 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第5期620-630,共11页
There is an increasing interest in bismuth carbonate(Bi2O2CO3,BOC)as a semiconductor photocatalyst.However,pure BOC strongly absorbs ultraviolet light,which drives a high recombination rate of charge carriers and ther... There is an increasing interest in bismuth carbonate(Bi2O2CO3,BOC)as a semiconductor photocatalyst.However,pure BOC strongly absorbs ultraviolet light,which drives a high recombination rate of charge carriers and thereby limits the overall photocatalysis efficiency.In this work,artificial oxygen vacancies(OV)were introduced into BOC(OV-BOC)to broaden the optical absorption range,increase the charge separation efficiency,and activate the reactants.The photocatalytic removal ratio of NO was increased significantly from 10.0%for pure BOC to 50.2%for OV-BOC because of the multiple roles played by the oxygen vacancies.These results imply that oxygen vacancies can facilitate the electron exchange between intermediates and the surface oxygen vacancies in OV-BOC,making them more easily destroyed by active radicals.In situ DRIFTS spectra in combination with electron spin resonance spectra and density functional theory calculations enabled unraveling of the conversion pathway for the photocatalytic NO oxidation on OV-BOC.It was found that oxygen vacancies could increase the production of active radicals and promote the transformation of NO into target products instead of toxic byproducts(NO2),thus the selectivity is significantly enhanced.This work provides a new strategy for enhancing photocatalytic activity and selectivity. 展开更多
关键词 Bismuth carbonate Oxygen vacancy Visible light photocatalysis Reactant activation Photocatalysis mechanism
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Synergistic integration of metallic Bi and defects on BiOI: Enhanced photocatalytic NO removal and conversion pathway 被引量:8
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作者 Minglu Sun Wendong Zhang +2 位作者 Yanjuan Sun Yuxin Zhang Fan Dong 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第6期826-836,共11页
Surface plasmon resonance(SPR)of metals may provide a way to improve light absorption and utilization of semiconductors,achieving better solar light conversion and photocatalysis efficiency.This study uses the advanta... Surface plasmon resonance(SPR)of metals may provide a way to improve light absorption and utilization of semiconductors,achieving better solar light conversion and photocatalysis efficiency.This study uses the advantages of SPR in metallic Bi and artificial defects to cooperatively enhance the photocatalytic performance of BiOI.The catalysts were prepared by partial reduction of BiOI to form Bi@defective BiOI,which showed highly enhanced visible photocatalytic activity for NOx removal.The effects of reductant quantity on the photocatalytic performance of Bi@defective BiOI were investigated.The as-prepared photocatalyst(Bi/BiOI-2)using 2 mmol of reductant NaBH4 showed the most efficient visible light photocatalytic activity.This enhanced activity can be ascribed to the synergistic effects of metallic Bi and oxygen vacancies.The electrons from the valence band tend to accumulate at vacancy states;therefore,the increased charge density would cause the adsorbed oxygen to transform more easily into superoxide radicals and,further,into hydroxyl radicals.These radicals are the main active species that oxidize NO into final products.The SPR effect of elemental Bi enables the improvement of visible light absorption efficiency and the promotion of charge carrier separation,which are crucial factors in boosting photocatalysis.NO adsorption and reaction processes on Bi/BiOI-2 were dynamically monitored by in situ infrared spectroscopy(FT-IR).The Bi/BiOI photocatalysis mechanism co-mediated by elemental Bi and oxygen vacancies was proposed based on the analysis of intermediate products and DFT calculations.This present work could provide new insights into the design of high-performance photocatalysts and understanding of the photocatalysis reaction mechanism for air-purification applications. 展开更多
关键词 Surface plasmon resonance Bi metal BiOI PHOTOCATALYSIS Oxygen vacancy Reaction mechanism
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Infrared Spectroscopy of Neutral Clusters Based on a Vacuum Ultraviolet Free Electron Laseri 被引量:1
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作者 Gang Li Chong Wang +4 位作者 Hui-jun Zheng Tian-tong Wang Hua Xie Xue-ming Yang Ling Jiang 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2021年第1期51-60,I0011,共11页
Spectroscopic characterization of clusters is crucial to understanding the structures and reaction mechanisms at the microscopic level,but it has been proven to be a grand challenge for neutral clusters because the ab... Spectroscopic characterization of clusters is crucial to understanding the structures and reaction mechanisms at the microscopic level,but it has been proven to be a grand challenge for neutral clusters because the absence of a charge makes it di伍cult for the size selection and detection.Infrared(IR)spectroscopy based on threshold photoionization using a tunable vacuum ultraviolet free electron laser(VUV-FEL)has recently been developed in the lab.The IR-VUV depletion and IR+VUV enhancement spectroscopic techniques open new avenues for size-selected IR spectroscopies of a large variety of neutral clusters without confinement(i.e.,an ultraviolet chromophore,a messenger tag,or a host matrix).The spectroscopic principles have been demonstrated by investigations of some neutral water clusters and some metal carbonyls.Here,the spectroscopic principles and their applications for neutral clusters are reviewed. 展开更多
关键词 CLUSTERS Infrared spectroscopy Vacuum ultraviolet free electron laser STRUCTURES Reaction mechanisms
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Mechanism and Kinetics of Polychlorination of Long Chain n-Alkanes by Photo-Initiation 被引量:1
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作者 易玲敏 詹晓力 陈丰秋 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2004年第5期647-651,共5页
Based on the mechanism analysis of the polychlorination of long chain n-alkanes by photo-initiation,a kinetic model was developed. The model parameters were obtained by the method of non-linear fitting. The influences... Based on the mechanism analysis of the polychlorination of long chain n-alkanes by photo-initiation,a kinetic model was developed. The model parameters were obtained by the method of non-linear fitting. The influences of luminous intensity and concentration of molecular chlorine on the rate of polychlorination are demonstrated by the model. If the luminous intensity is adequate, the polychlorination rate of n-alkane is only controlled by the flow rate of molecular chlorine in a wide range of temperature, and the changes of temperature and luminous intensity have less effect on the reaction rate. In addition, the predictions of chlorine content of polychlorinated n-alkane calculated with the model agree very well with experimental results. 展开更多
关键词 PHOTOCHLORINATION polychlorination photo-initiation chlorination longchain n-alkanes MECHANISM KINETICS
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Recent progress in production and usage of hydrogen peroxide 被引量:10
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作者 Shunichi Fukuzumi Yong-Min Lee Wonwoo Nam 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第8期1241-1252,共12页
Hydrogen peroxide has attracted increasing interest as an environmentally benign and green oxidant that can also be used as a solar fuel in fuel cells.This review focuses on recent progress in production of hydrogen p... Hydrogen peroxide has attracted increasing interest as an environmentally benign and green oxidant that can also be used as a solar fuel in fuel cells.This review focuses on recent progress in production of hydrogen peroxide by solar-light-driven oxidation of water by dioxygen and its usage as a green oxidant and fuel.The photocatalytic production of hydrogen peroxide is made possible by combining the e^(-)and 4e-oxidation of water with the e^(-)reduction of dioxygen using solar energy.The catalytic control of the selectivity of the e^(-)vs.4e-oxidation of water is discussed together with the selectivity of the e^(-)vs.4e-reduction of dioxygen.The combination of the photocatalytic e^(-)oxidation of water and the e^(-)reduction of dioxygen provides the best efficiency because both processes afford hydrogen peroxide.The solar-light-driven hydrogen peroxide production by oxidation of water and by reduction of dioxygen is combined with the catalytic oxidation of substrates with hydrogen peroxides,in which dioxygen is used as the greenest oxidant. 展开更多
关键词 Hydrogen peroxide production Water oxidation Dioxygen reduction Photocatalytic oxygenation Reaction kinetics and mechanism
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Photocatalytic activity of CuO towards HER in catalyst from oxalic acid solution under simulated sunlight irradiation 被引量:7
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作者 姚茂海 唐有根 +2 位作者 张丽 杨海华 阎建辉 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第10期1944-1949,共6页
CuO was synthesized by thermal decomposition of Cu(NO3)2·3H2O at various temperatures and characterized by powder X-ray diffractometry(XRD) as well as scanning electron microscopy(SEM).The effects of calcination ... CuO was synthesized by thermal decomposition of Cu(NO3)2·3H2O at various temperatures and characterized by powder X-ray diffractometry(XRD) as well as scanning electron microscopy(SEM).The effects of calcination temperature,category of sacrificial reagent,initial sacrificial reagent concentration,and Ag loading content on the photocatalytic activity of the as-obtained CuO sample were investigated.The results show that the as-obtained CuO exhibits high activity for photocatalysis of H2 evolution reaction(HER) in oxalic acid solution under simulated sunlight irradiation.The highest photocatalytic activity of the as-obtained CuO was achieved at the calcination temperature of 1000℃,and oxalic acid was used as the sacrificial reagent with the concentration 0.05 mol/L.H2 evolution rate is as high as 2.98 mmol/(h·g) with 2%(mass fraction) loaded Ag.The possible photocatalytic reaction mechanism on the CuO photocatalyst for HER in oxalic acid solution was also discussed. 展开更多
关键词 copper oxide (CuO) hydrogen evolution reaction (HER) photocatalytic activity oxalic acid simulated sunlight
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Experimental Study of Premixed Stoichiometric Ethylene/Oxygen/Argon Flame
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作者 Qing Zhang Yu-yang Li +3 位作者 Zhen-yu Tian Tai-chang Zhang Jing Wang Fei Qi 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2006年第5期379-385,共7页
A comprehensive experimental study of the premixed ethylene/oxygen/argon flame at 2.667 kPa with a stoichiometric equivalence ratio (Ф=1) was performed with the tunable synchrotron photoionization and molecular-bea... A comprehensive experimental study of the premixed ethylene/oxygen/argon flame at 2.667 kPa with a stoichiometric equivalence ratio (Ф=1) was performed with the tunable synchrotron photoionization and molecular-beam sampling mass spectrometry techniques. The isomers of most observed species in the flame were unambiguously identified by measurements of the photoionization etticiency spectra, e.g. C3H4, C2H4O and C4H4. The mole fraction profiles of species up to C7H8 were measured by scanning the burner position at the selected photon energies near ionization thresholds, and the flame temperature profile was obtained by using Pt/Pt-13%Rh thermocouple. Compared with the previous studies, a lot of new flame species: C3H2, C3H3, C3H5, C2H6O, C4H2, C4H4, C4H6, C3H4O, C3H6O, C3H8O, C5H6, C4H8O and C7H8, were observed. A series of free radicals in the flame are detected to be CH3, C2H3, C2H5, HCO, C3H3 and C3H5. Based on the experimental work, a reduced reaction mechanism was developed including 40 species and 223 reactions. Modeling and measurements agree well for the major species and most intermediates. A detailed kinetic model is desired for this flame. 展开更多
关键词 Premixed ethylene/oxygen flame Tunable synchrotron photoionization Reaction mechanism
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Theoretical Investigations on Photodissociation Dynamics of Deuterated Alkyl Halides CD_(3)CH_(2)F
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作者 Shuangfei Gu Chih-Hao Chin +1 位作者 Tong Zhu John Zeng Hui Zhang 《Chinese Journal of Chemical Physics》 SCIE EI CAS CSCD 2022年第3期431-442,I0001,共13页
The product branching ratio between different products in multichannel reactions is as important as the overall rate of reaction,both in terms of practical applications(e.g.models of combustion or atmosphere chemistry... The product branching ratio between different products in multichannel reactions is as important as the overall rate of reaction,both in terms of practical applications(e.g.models of combustion or atmosphere chemistry)in understanding the fundamental mechanisms of such chemical reactions.A global ground state potential energy surface for the dissociation reaction of deuterated alkyl halide CD_(3)CH_(2)F was computed at the CCSD(T)/CBS//B3 LYP/aug-cc-p VDZ level of theory for all species.The decomposition of CD_(3)CH_(2)F is controversial concerning C-F bond dissociation reaction and molecular(HF,DF,H_(2),D_(2),HD)elimination reaction.RiceRamsperger-Kassel-Marcus(RRKM)calculations were applied to compute the rate constants for individual reaction steps and the relative product branching ratios for the dissociation products were calculated using the steady-state approach.At the different energies studied,the RRKM method predicts that the main channel for DF or HF elimination from1,2-elimination of CD_(3)CH_(2)F is through a four-center transition state,whereas D_(2) or H_(2) elimination from 1,1-elimination of CD_(3)CH_(2)F occurs through a direct three-center elimination.At 266,248,and 193 nm photodissociation,the main product CD_(2)CH_(2)+DF branching ratios are computed to be 96.57%,91.47%,and 48.52%,respectively;however,at 157 nm photodissociation,the product branching ratio is computed to be 16.11%.Based on these transition state structures and energies,the following photodissociation mechanisms are suggested:at 266,248,193 nm,CD_(3)CH_(2)F→absorption of a photon→TS5→the formation of the major product CD_(2)CH_(2)+DF;at 157 nm,CD_(3)CH_(2)F→absorption of a photon→D/F interchange of TS1→CDH_(2)CDF→H/F interchange of TS2→CHD_(2)CHDF→the formation of the major product CHD_(2)+CHDF. 展开更多
关键词 Potential energy surface Photodissociation dynamics Reaction mechanism Rate constant Branching ratio
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Research Progress on the Synthesis of Benzofuran Based on Cyclization Strategy
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作者 Jin Ruiwen Wang Lianjie +3 位作者 Song Yue Liu Xiaopei Wang Junwei Li Zhongxian 《有机化学》 SCIE CAS CSCD 北大核心 2024年第9期2742-2759,共18页
Benzofuran is an essential structural component found in a wide range of natural products,agrochemicals and drugs,possessing a range of biological activities.In recent years,there have been numerous reports of success... Benzofuran is an essential structural component found in a wide range of natural products,agrochemicals and drugs,possessing a range of biological activities.In recent years,there have been numerous reports of successful syntheses of benzofuran derivatives via intra-and inter-molecular cyclizations using diverse catalysts.This review gives an exhaustive and methodical survey of the procedures for making benzofurans. 展开更多
关键词 BENZOFURANS metal-catalyzed reactions electrochemical reactions photochemical reactions mechanistic pathway
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Mechanistic study and kinetic properties of the CF_3CHO+Cl reaction
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作者 GAO Hong WANG Ying +1 位作者 WANG Qin LIU JingYao 《Science China Chemistry》 SCIE EI CAS 2012年第10期2197-2201,共5页
Theoretical investigations have been carried out on the mechanism and kinetics for the reaction of CF 3 CHO + Cl using duallevel direct dynamics method. The potential energy surface information was obtained at the MCQ... Theoretical investigations have been carried out on the mechanism and kinetics for the reaction of CF 3 CHO + Cl using duallevel direct dynamics method. The potential energy surface information was obtained at the MCQCISD/3//MP2/cc-pVDZ level and the kinetic calculations were done using variational transition state theory with interpolated single-point energy (VTST-ISPE) approach. The calculated results show that the reaction proceeds primarily via the H-abstraction channel, while the Cl-addition channel is unfavorable due to the higher barriers. The improved canonical variational transition-state theory (ICVT) with the small-curvature tunneling correction (SCT) was used to calculate the rate constants. The theoretical rate constants at room temperature are in general agreement with the experimental values. A three-parameter rate constant expression was fitted over a wide temperature range of 200-2000 K. 展开更多
关键词 direct dynamics rate constant variational transition-state theory
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