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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

Effect on electrochemical reduction of nitrogen to ammonia under ambient conditions: Challenges and opportunities for chemical fuels

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Journal of Energy Chemistry 2021年第10期30卷 304-318,I0009页

作者： Lijuan Niu Li An Xiayan Wang Zaicheng Sun Beijing Key Laboratory for Green Catalysis and Separation Center of Excellence for Environmental Safety and Biological EffectsFaculty of Environment and LifeBeijing University of TechnologyBeijing 100124China

The nitrogen cycle plays an important role in nature,but N-containing products cannot meet human *** electrochemical synthesis of ammonia under ambient conditions has attracted the interest of many researchers because it provides a clean and pollution-free synthesis method;however,it has certain difficulties,including a high activation energy,multiple electron transfer,and *** factors limit the selectivity and activity of ammonia synthesis *** review summarizes progress in the electrochemical synthesis of ammonia from theory and ***,the reduction of nitrogen molecules is analyzed using orbit theory and the thermodynamic reaction ***,we first discuss the effect of the experimental setup on the nitrogen reduction reaction,and then the four critical of catalysts,including size,electronic,coordination,and orientation *** issues must be considered to produce highly-efficient catalysts for electrochemical nitrogen reduction(eNRR).This review provides an overview of the eNRR to enable future researchers to design rational catalysts.

关键词： Nitrogen reduction reaction NRR Electrocatalyst Nitrogen-fixing

Efficient photocatalytic overall water splitting achieved with polymeric semiconductor-based Z-scheme heterostructures

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Science China Chemistry 2021年第6期64卷 875-876页

作者： Xupeng Zong Wenshuai Jiang Zaicheng Sun center of excellence for environmental safety and biological effects Beijing Key Laboratory for Green Catalysis and SeparationDepartment of Chemistry and BiologyBeijing University of TechnologyBeijing 100124China

Developing new technology to utilize solar power as alternative energy is imperative to meet the challenge of fossil fuel consumption and consequently environmental *** overall water splitting is regarded as an ideal reaction for realizing solar-to-chemical energy *** to date,many particle-suspension systems have been studied on a laboratory-scale with inorganic semiconductors including metal oxides,(oxy)nitrides.

关键词： splitting utilize polymeric

The critical factors of photocatalytic H2 production from seawater by using TiO_(2)as photocatalyst

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Nano Research 2023年第4期16卷 4620-4624页

作者： Yaqian He Pengfei Li Wenning Liu Li An Dan Qu Xiayan Wang Zaicheng Sun Beijing Key Laboratory for Green Catalysis and Separation Center of Excellence for Environmental Safety and Biological EffectsFaculty of Environment and LifeBeijing University of TechnologyBeijing 100124China

The solar H_(2)generation directly from natural seawater is a sustainable way of green ***,it is limited by a low H_(2)generation rate even compared to fresh *** this report,TiO_(2)is chosen as a model photocatalyst to disclose the critical factor to deteriorate the H_(2)generation rate from *** simulated seawater(SSW),which is composed of eight ions(Na^(+),K^(+),Ca^(2+),Mg^(2+),Cl^(−),Br^(−),SO_(4)^(2−),and CO_(3)^(2−)),is investigated the effect of each ion on the H_(2)*** results indicate that all ions have a negative effect at the same concentration as in the seawater except Br−.The CO_(3)^(2−)has the most serious deterioration,and the H_(2)production rate lowers near 40%even at[CO_(3)^(2−)]of 1.5 mmol·L^(−1).The H_(2)production rate can be recovered to 85%if the CO_(3)^(2−)is excluded from the *** understand the reason,the zeta potential of the TiO_(2)treated with different ions aqueous solution reveals that the zeta potential decreases when it is treated with CO_(3)^(2−)and SO_(4)^(2−)due to they can adsorb on the surface of TiO_(2)*** transform infrared(FTIR)and thermogravimetric analysis-mass spectroscopy(TGA-MS)further confirm that the adsorbed ion is mainly from CO_(3)^(2−).Since the pH of seawater is about 8.9 between pKa1(6.37)and pKa2(10.3)of H_(2)CO3,the CO_(3)^(2−)should exist in the form of HCO3−in the *** proposed a simple method to remove the adsorbed HCO3−from the TiO_(2)surface by adjusting the pH below the *** results indicate that if a trace amount of HCl(adjusting pH~6.0)is added to the SSW,the H_(2)production rate can be recovered to 85%of that in pure water.

关键词： seawater H_(2)production rate adsorb ions pH

Development of Ultranarrow-Bore Open Tubular High Efficiency Liquid Chromatography

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Chinese Journal of Chemistry 2022年第1期40卷 137-152页

作者： Yingyan Zhou Guangsheng Guo Xiayan Wang center of excellence for environmental safety and biological effects Beijing Key Laboratory for Green Catalysis and SeparationDepartment of Chemistry and BiologyBeijing University of TechnologyBeijing 100124China

Chromatography theory shows that when the inner diameter of the chromatography column is very narrow(e.g.,1—2μm),the maximum efficiency will be produced in liquid *** addition,the increasing demand for ultrasmall volume sample analysis has produced the trend of narrowing the diameter of the liquid chromatography *** have verified that ultranarrow-bore open tubular liquid chromatography(i.d.≤2μm)has the advantages of small sample requirement and high separation ***,there also exist huge challenges along with such obvious *** review summarizes the efforts made by our research group and other research groups to develop this *** hope that in the near future,ultranarrow bore open-tube liquid chromatography can be successfully and maturely applied to the application of analytes with ultrasmall size and volume such as single-cell and even subcellular organelles omics research.

关键词： Ultra narrow-bore Liquid chromatography Ultrahigh separation efficiency Pico-PLOT column Analytical methods

An innovative way to modulate the photoluminescence of carbonized polymer dots

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Light(Science & Applications) 2022年第5期11卷 724-726页

作者： Pengfei Li Zaicheng Sun center of excellence for environmental safety and biological effects Beijing Key Laboratory for Green Catalysis and SeparationFaculty of Environment and LifeBeijing University of TechnologyBeijing 100124P.R.China

Cross-linking enhances the photoluminescence quantum yield of carbonized polymer dots,in which confined-domain promotes the energy level overlap,redshifts emission wavelength,and facilitates phosphorescence generation.

关键词： linking overlap polymer

Recent advances of carbon dots as new antimicrobial agents

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SmartMat 2022年第2期3卷 226-248页

作者： Pengfei Li Lu Sun Shanshan Xue Dan Qu Li An Xiayan Wang Zaicheng Sun Department of Chemistry and Biology Beijing Key Laboratory for Green Catalysis and SeparationCenter of Excellence for Environmental Safety and Biological EffectsBeijing University of TechnologyBeijingChina

Due to the COVID-19 pandemic,many rapid antimicrobial agents have developed *** dots(CDs),a new type of carbon-based nanomaterials,shows great potential against emerging infectious diseases and antimicrobial-resistant infections due to their unique optical properties,excellent biocompatibility,and easy surface *** the definition of the CDs structure and properties,synthesis,and characteristic technology improvement,the research on the CDs as antimicrobial agents has made significant ***,the lack of high repeatable and exact preparation methods,and the regular antimicrobial activity make it far from practical *** this review,we summarize the most recent progress and challenges of CDs ***,an overview of the characteristics and properties is given,and the advantage of CDs applied to antimicrobial is further ***,it focuses on research progress on antimicrobial mechanisms under different conditions,the critical factors affecting their antimicrobial activity,and the practical antimicrobial ***,the main challenges and future research perspectives of antimicrobial CDs are proposed.

关键词： antimicrobial antimicrobial activity carbon dots photodynamic effect reactive oxygen species

A metal-free carbon dots for wastewater treatment by visible light active photo-Fenton-like reaction in the broad pH range

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Chinese Chemical Letters 2021年第7期32卷 2292-2296页

作者： Dongxue Yang Dan Qu Li An Xupeng Zong Zaicheng Sun center of excellence for environmental safety and biological effects.Beijing Key Laboratory for Green Catalysis and Separation Department of Chemistry and BiologyBeijing University of TechnologyBeijing 100124China

Carbon dots(Cdots)has been proved to possess the catalytic decomposition of H_(2)O_(2) in the photocatalytic *** is a potential photo-Fenton *** multiple emissive Cdots have different light response *** is rarely investigation on the performance of Cdots based photo-Fenton on the light ***,blue,green and red emissive carbon dots were synthesized from the different ratio of o-phenylenediamine and catechol by the solvothermal *** exhibit different light adsorption range from UV to visible ***,the photo-Fenton reactivity of Cdots was studied for catalyzing the decomposition of H_(2)O_(2) to generate free hydroxyl radicals and consequently applying for the removal of methyl *** results exhibit that Cdots with the broader light adsorption rang possess the stro nger catalytic activity for the photo-Fenton *** H_(2)O_(2) decomposition rate of red emissive Cdots is 0.074 min^(-1),which is 2.64 and 1.46 times than the blue and green emissive Cdots,*** the radical detection results confirm that the photo-Fenton happens in the *** addition,the Cdots photo-Fenton can be carried out in the broad pH range from acidic to basic solution,which has a great potential to treat wastewater in the neutral system.

关键词： Carbon dot Photo-Fenton reaction H_(2)O_(2) Visible light Wastewater treatment

Nano-sized stationary phase packings retained by single-particle frit for microchip liquid chromatography

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Chinese Chemical Letters 2024年第4期35卷 486-489页

作者： Wangyan Hu Ke Li Xiangnan Dou Ning Li Xiayan Wang center excellence for environmental safety and biological effects Beijing Key Laboratory for Green Catalysis and SeparationDepartment of ChemistryBeijing University of TechnologyBeijing 100124China center for environmental Metrology National Institute of MetrologyBeijing 100029China

Modern chromatography is increasingly focused on miniaturization and integration. Compared to conventional liquid chromatography, microfluidic chip liquid chromatography(microchip-LC) has the potential due to its zero-dead volume connection and ease of integration. Nano-sized packings have the potential to significantly enhance separation performance in microchip-LC. However, their application has been hindered by packing difficulties. This study presents a method for packing nano-sized silica particles into a microchannel as the stationary phase. The microchip-LC packed column was prepared by combining the weir and the porous silica single-particle as frit to retain the packing particles. A surface tensionbased single-particle picking technique was established to insert porous single-particle frit into glass microchannels. Additionally, we developed a slurry packing method that utilizes air pressure to inject nano-sized packing into the microchannel. Pressure-driven chromatographic separation was performed using this nano-packed column integrated into a glass microchip. The mixture of four PAHs was successfully separated within just 8 min using a 5 mm separation channel length, achieving high theoretical plates(10~6plates/m). Overall, these findings demonstrate the potential of utilizing nano-sized packings for enhancing chromatographic performance in microchip systems.

关键词： Nano-size packing Single-particle frit Packed column Microchip LC Chromatographic separation