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Formation and fluorescent mechanism of red emissive carbon dots from o-phenylenediamine and catechol system

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Light(Science & Applications) 2022年第11期11卷 2687-2697页

作者： Pengfei Li Shanshan Xue Lu Sun Xupeng Zong Li An Dan Quo Xiayan Wang Zaicheng Sun Center of Excellence for Environmental Safety and Biological Effects Bejing Key Laboratory for Green Catalysis and SeparationDepartment of ChemistryBeijing Universityof Technology100124 BejingChina

Carbon dots(CDs)as the advancing fluorescent carbon nanomaterial have superior potential and ***,the ambiguous photoluminescence(PL)mechanism and intricate structure-function relationship become the greatest hindrances in the development and applications of ***,red emissive CDs were synthesized in high yield from O-phenylenediamine(oPD)and catechol(CAT).The PL mechanism of the CDs is considered as the molecular state fluorophores because 5,14-dihydroquinoxalino[2,3-b]phenazine(DHQP)is separated and exhibits the same PL properties and behavior as the *** include the peak position and shape of the PL emission and PL excitation and the emission dependence on pH and solvent *** of them display close PL lifetime *** on these,we deduce that DHQP is the fluorophore of the red emissive CDs and the PL mechanism of CDs is similar to *** the PL emission of CDs,the electron of the molecule state can transfer to *** formation process of DHQP is further confirmed by the reaction intermediates(phthalazine,dimers)and *** findings provide insights into the PL mechanism of this type of CDs and may guide the further development of tunable CDs for tailored properties.

关键词： properties mechanism catechol

Vapour-phase O-methylation of catechol with Methanol on Ti-containing Phosphate Catalysts

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Chemical Research in Chinese Universities 2006年第4期22卷 533-536页

作者： ZHU Xiao-mei LI Xue-mei LIU Gang ZOU Xiu-jing WANG Yan-li JIA Ming-jun ZHANG Wen-xiang College of Chemistry Jilin University Changchun 130021 P. R. China Shanghai Huayi Acrylic Acid Co. Ltd. Shanghai 200137 P. R. China

Ti-containing phosphate（ Ti-P-O ） catalysts with different molar ratios of P to Ti （0--2. 0 ） were synthesized and characterized by XRD, N2-adsorption/desorption, IR and temperature-programmed desorption （TPD） methods. The catalytic properties of Ti-P-O samples in the vapor-phase O-methylation of catechol with methanol were also studied. The catechol conversion increases with the increase of the molar ratio of P to Ti in a range of 0-0. 33, while a further increase in the P content leads to a decrease of the catalytic activity. Meanwhile, the selectivities of the catalysts to the main product（guaiacol） increase gradually with the increase of the molar ratio of P to Ti. The presence of relatively strong Lewis acidic and/or basic sites in the P-free catalyst should be responsible for the formation of C-alkylation products. The weak acid-base characteristics of the catalysts are favourable for the mono-O-methylation of catechol. In comparison with the Lewis acidic sites, the Bronsted acidic sites on the catalysts are more active for the title reaction.

关键词： Phosphates Acid-base catalysis Guaiacol catechol O-Methylation

Unravelling the effects of complexation of transition metal ions on the hydroxylation of catechol over the whole pH region

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Journal of Environmental Sciences 2022年第5期34卷 392-402页

作者： Zexiu An Jianfei Sun Qiong Mei BoWei Mingxue Li Ju Xie Maoxia He Qiao Wang Environment Research Institute Shandong UniversityQingdao 266237China School of Environmental and Materials Engineering Yantai UniversityYantai 264005China College of Safety and Environmental Engineering Shandong University of Science and TechnologyQingdao 266590China School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou 225002China

catechol pollutants(CATPs)serving as chelating agents could coordinate with many metal ions to form various CATPs-metal *** information is available on the effects of complexation of metal ions on CATPs *** work presents a systematical study of·OH-mediated degradation of catechol and catechol-metal complexes over the whole pH range in advanced oxidation processes(AOPs).Results show that the pH-dependent complexation of metal ions(Zn^(2+),Cu^(2+),Ti^(4+)and Fe^(3+))promotes the deprotonation of catechol under neutral and even acidic *** radical adduct formation(RAF)reactions are both thermodynamically and kinetically favorable for all dissociation and complexa-tion species,and-OH/-O-group-containing C positions are more vulnerable to·OH *** kinetic results show that the complexation of the four metal ions offers a wide pH range of effectiveness for catechol *** pH 7,the apparent rate constant(k_(app))values for different systems follow the order of catechol+Ti^(4+)≈catechol+Zn^(2+)>catechol+Cu^(2+)>catechol+Fe^(3+)>*** mechanistic and kinetic results would greatly improve our understanding of the degradation of CATPs-metal and other organics-metal complexes in *** toxicity assessment indicates that the·OH-based AOPs have the ability for decreasing the toxicity and increasing the biodegradability during the processes of catechol degradation.

关键词： catechol Metal ions Complexation pH Degradation

Adsorption of catechol from aqueous solution by aminated hypercrosslinked polymers

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Journal of Environmental Sciences 2005年第4期17卷 584-588页

作者： SUNYue LIXiao-tao XUChao CHENJin-long LIAi-min ZHANGQuan-xing StateKeyLaboratoryofPollutionControlandResourcesReuse SchooloftheEnvironmentNanjingUniversityNanjing210093China.

Adsorption of catechol from aqueous solution with the hypercrosslinked polymeric adsorbent NDA-100 and its derivatives AH-1, AH-2 and AH-3 aminated by dimethylamine, the commercial resin Amberlite XAD-4 and weakly basic anion exchanger resin D301 was compared. It was found that the aminated hypercrosslinked resins had the highest adsorption capacities among the tested polymers. The empirical Freundlich equation was successfully employed to describe the adsorption process. Specific surface area and micropore structure of the adsorbent, in company with tertiary amino groups on matrix affected the adsorption performance towards catechol. In addition, thermodynamic study was carried out to interpret the adsorption mechanism. Kinetic study testified that the tertiary amino groups on the polymer matrix could decrease the adsorption rate and increase the adsorption apparent activation energy.

关键词： hypercrosslinked polymer catechol adsorption thermodynamics kinetics

Underpotential Deposition Preparation of Pt-loading AuNPs/Reduced Graphene Oxide and Its Catalytic Detection of catechol

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Chinese Journal of Chemistry 2016年第11期34卷 1151-1157页

作者： Cong Wang Zhihua Guo Li Zhang Na Zhang Keying Zhang Bailu Fei Hongyan Wang Jigui Xu Hongwei Shi Miao Qin Lei Ren Xingxing Wu A nhui Key Laboratory of Spin Electron and Nanomaterials School of Chemistry and Chemical Engineering Suzhou University Suzhou Anhui 234000 China School of Biology and Food Engineering Suzhou University Suzhou Anhui 234000 China College of Chemistry and Materials Science Anhui Normal University Wuhu Anhui 241000 China

Ultralow Pt-loading Au nanoparticles have been fabricated on the surface of reduced graphene oxide （RGO） by using underpotential deposition （UPD） monolayer redox replacement process. The Pt/Au/RGO modified electrode exhibits an excellent electrocatalytic activity toward catechol and hydroquinone. Under the optimized condition, the separation of peak-to-peak between hydroquinone and catechol is 197 mV, which is wide enough to distinguish the isomers of benzenediol. catechol is detected by the Pt/Au/RGO/GCE with a low detection limit in the presence of hydroquinone.

关键词： reduced graphene oxide catechol underpotential deposition Pt-loading Au nanoparticles

Fluorescence quenching method for the determination of catechol with gold nanoparticles and tyrosinase hybrid system

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Chinese Chemical Letters 2010年第3期21卷 346-348页

作者： Martin M.F.Choi Department of Chemistry Hong Kong Baptist University

The determination method of catechol by fluorescence quenching was *** assay was based on the combination of the unique property of gold nanoparticles with tyrosinase enzymatic *** the presence of tyrosinase,the fluorescence of gold nanoparticles was quenched by catechol which can be employed to detect *** the optimal conditions,a linear range 5.0×10^(-7)-1.0×10^(-3) mol L^(-1) and a detection limit 1.0×10^(-7) mol L^(-1) of catechol were obtained.o-Quinone intermediate produced...

关键词： Gold nanoparticles Tyrosinase catechol Fluorescence quenching

Hydroxylation Reaction of Phenol to catechol on Lanthanide-Zirconia Catalyst

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Journal of Rare Earths 1996年第4期14卷 295-297页

作者：邓国才刘歆颖徐莉李梦青马洪涛穆瑞才刘靖疆陈荣悌 NANKAI UNIV DEPT CHEMTIANJIN 300071PEOPLES R CHINA

The selective H2O2 oxidation reaction of phenol to catechol on Ln-ZrO2 catalyst has improved the selectivity to 85%, to compare with the conventional titania catalyst. With addition of rare earth such as lanthanum, neodymium, to zirconia as catalyst, the selectivity is increased by 72% and 60% respectively in comparison with the bare titania catalyst.

关键词： catechol rare earth catalyst zirconia phenol hydroxylation

Electroless deposition of Au nanoparticles on reduced graphene oxide/polyimide film for electrochemical detection of hydroquinone and catechol

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Frontiers of Materials Science 2017年第3期11卷 262-270页

作者： Xuan SHEN Xiaohong XIA Yongling DU Chunming WANG College of Chemistry and Chemical Engineering Lanzhou University Lanzhou 730000 China

An electrochemical sensor for determination of hydroquinone （HQ） and catechol （CC） was developed using Au nanoparticles （AuNPs） fabricated on reduced graphene oxide/polyimide （PIIRGO） film by electroless deposition. The electrochemical behaviors of HQ and CC at PIIRGO-AuNPs electrode were investigated by cyclic voltammetry （CV） and differential pulse voltammetry （DPV）. Under the optimized condition, the current responses at PI/RGO-AuNPs electrode were linear over ranges from 1 to 654 mol/L for HQ and from 2 to 1289 mol/L for CC, with the detection limits of 0.09 and 0.2 mollL, respectively. The proposed electrode exhibited good reproducibility, stability and selectivity. In addition, the proposed electrode was successfully applied in the determination of HQ and CC in tap water and the Yellow River samples.

关键词： electroless Au nanoparticles hydroquinone catechol sensor

Investigation on the Electrochemical Polymerization of catechol by Means of Rotating Ring-disk Electrode

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Chinese Journal of Chemistry 2003年第6期21卷 630-637页

作者：孔泳穆绍林 Department of Chemistry Yangzhou University Yangzhou Jiangsu 225002 China

The electrolysis of catechol was studied in the pH values of 1 to 10. The results from the rotating ring disk electrode (RRDE) experiments show that at low pH values, the electrochemical polymerization of catechol was performed by one step, and at higher pH values, the electrochemical polymerization of catechol was carried out by two steps, i.e . oxidation of catechol and followed by polymerization. The intermediates generated at the disk were detected at the ring electrode in the ring potential region of -0.2 to 0 V (vs. Ag/AgCl). One of reasons for the decrease in the ratio of i r to i d with increasing the ring potential is caused by formation of positively charged intermediates at the disk electrode. This ratio increases with increasing the rotation rate of the RRDE, which indicates that the intermediates are not stable. A shielding effect during polymerization of catechol was observed when the ring potential was set at 0.1 V (vs. Ag/AgCl). The electron spin resonance (ESR) of polycatechol shows that polycatechol possesses unpaired electrons. The images of polycatechol films synthesized at different conditions are described.

关键词： electrochemical polymerization catechol rotating ring disk electrode intermediates electron spin resonance scanning electron micrographs