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Competitive assembling strategy to construct carbon nitride homojunctions for boosting photocatalytic performance

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Journal of Materials Science & Technology 2024年第5期172卷 23-32页

作者： Hua-wei Zhang Yuan-Yuan Li Bo Li Jing-Hui Shi Tao huang Gui-Fang huang Anlian Pan Wangyu Hu wei-qing huang School of Physics&Electronic Engineering Zhengzhou University of Light IndustryZhengzhou 450002China Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education&Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices School of Physics and ElectronicsHunan UniversityChangsha 410082China College of Materials Science and Engineering Hunan UniversityChangsha 410082China

Both morphology and composition have a great influence on the properties and functions of materials,however,how to rational modulate both of them to achieve their synergistic effects has been a longstanding ***,we demonstrate a competitive assembling strategy for the construction of metal-free graphite carbon nitride(CN)homojunctions in which morphology and composition can be easily controlled simultaneously by only changing the ratio of assembly raw *** homojunctions are comprised of porous nanotubular S-doped CN(SCN)grafted with CN nanovesicles,which are derived from thermal polycondensation of melamine-thiocyanuric acid(M-T)/melamine-cyanuric acid(M-C)supramolecular hybrid *** unique architecture and component engineering endows the novel SCN-CN homojunction with abundant active sites,enhanced visible trapping ability,and intimate interface *** a result,the synthesized SCN-CN homojunctions demonstrate high photocatalytic activity for hydrogen evolution and pollutant *** developed strategy opens up intriguing opportu-nities for the rational construction of intricate metal-free heterostructures with controllable architecture and interfacial contact for applications in energy-related fields.

关键词： Competitive assembling strategy Supramolecular hybrid blocks Homojunctions Graphite carbon nitride Photocatalytic

Facile synthesis and superior photocatalytic and electrocatalytic performances of porous B-doped g-C_3N_4 nanosheets

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Journal of Materials Science & Technology 2018年第12期34卷 2515-2520页

作者： Qian Yan Gui-Fang huang Dong-Feng Li Ming Zhang An-Lian Pan wei-qing huang Department of Applied Physics School of Physics and ElectronicsHunan University

As a low-cost visible-light-driven metal-free catalyst, graphitic carbon nitride(g-CN) has attracted increasing attention due to its wide applications for solar energy conversion, environmental purification,and organic photosynthesis. In particular, the catalytic performance of g-CNcan be easily modulated by modifying morphology, doping, and copolymerization. Simultaneous optimization, however, has little been achieved. Herein, a facile one-pot strategy is developed to synthesize porous B-doped g-CNnanosheets by using HBOand urea as the precursor during thermal polymerization. The resultant B-doped g-CNnanosheets retain the original framework of bulk g-CN, while induce prominently enhanced visible light harvesting and narrowing band gap by 0.32 eV compared to pure g-CN. Moreover, the adsorption capacity and photodegradation kinetics of methylene blue(MB) under visible light irradiation over B-doped g-CNnanosheets can be improved by 20.5 and 17 times, respectively. The synthesized porous B-doped g-CNnanosheets also exhibit higher activities than pure g-CNas bifunctional electrocatalyst for both oxygen evolution reaction(OER) and oxygen reduction reaction(ORR). The enhanced catalyst performance of porous B-doped g-CNnanosheets stems from the strong synergistic effect originating from the larger exposed active sites generated by the exfoliation of g-CNinto nanosheets and the porous structure, as well as the better conductivity owing to B-doping. This work provides a simple, effective, and robust method for the synthesis of g-CN-based nanomaterial with superior properties to meet the needs of various applications.

关键词： B-doped g-C_3N_4 nanosheets Photocatalysts Electrocatalysts

Acid-induced topological morphology modulation of graphitic carbon nitride homojunctions as advanced metal-free catalysts for OER and pollutant degradation

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Journal of Materials Science & Technology 2021年第27期86卷 210-218页

作者： Hua-wei Zhang Yi-Xin Lu Bo Li Gui-Fang huang Fan Zeng Yuan-Yuan Li Anlian Pan Yi-Feng Chai wei-qing huang Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education&Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices School of Physics and ElectronicsHunan UniversityChangsha410082China College of Materials Science and Engineering Hunan UniversityChangshaHunan410082China School of Physics and Electronics Science Hunan University of Science and TechnologyXiangtan411201China

Topological morphology that dominates the surface electronic properties of nanostructures plays a key role in producing desired materials for versatile functions and applications in many fields,but its modulation for specific functions remains a big ***,we report an acid-induced method to prepare S-doped graphitic carbon nitride/graphitic carbon nitride(S-CN/CN)homojunction by simply pyrolyzing a supramolecular precursor synthesized from melamine and H_(2)SO_(4).The topological morphology and electronic structure of CN homojunction can be easily adjusted only by changing the ratio of raw ***,the topological morphology of S-CN/CN homojunction can be further adjusted from hollow cocoon to 2D nanosheets by changing the annealing *** optimized S-CN/CN homojunction shows highly efficient in charge transfer and separation and exhibits superior OER activity and high ability to degrade organic ***,S-CN/CN nanosheets only demand low overpotential of301 m V to drive a current density of 10 m Acm^(-2)in 1 M KOH media,and the corresponding Tafel slope is only 57.71 m V/dec,which is superior to the most advanced precious metal Ir O_(2)***,under visible light irradiation,its photodegradation kinetic rate of Rh B is 2.38,which is 47.6 times higher than that of bulk *** work provides useful guidance for designing and developing efficient multifunctional metal-free catalysts.

关键词： Topological morphology Acid-induced Molecular self-assembly S-CN/CN homojunction OER

Chlorine doped graphitic carbon nitride nanorings as an efficient photoresponsive catalyst for water oxidation and organic decomposition

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Journal of Materials Science & Technology 2019年第10期35卷 2288-2296页

作者： Er-Xun Han Yuan-Yuan Li Qi-Hao Wang wei-qing huang Leng Luo Wangyu Hu Gui-Fang huang Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education&Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices School of Physics and ElectronicsHunan UniversityChangsha 410082China School of Materials Science and Engineering Hunan UniversityChangsha 410082China

Rationally engineering the microstructure and electronic structure of catalysts to induce high activity for versatile applications remains a challenge. Herein, chlorine doped graphitic carbon nitride(Cl-doped g-C3N4) nanorings have been designed as a superior photocatalyst for pollutant degradation and oxygen evolution reaction(OER). Remarkably, Cl-doped g-C3N4 nanorings display enhanced OER performance with a small overpotential of approximately 290 m V at current density of 10 m A cm^-2 and Tafel slope of 83 m V dec-1, possessing comparable OER activity to precious metal oxides RuO2 and IrO2/C. The excellent catalytic performance of Cl-doped g-C3N4 nanorings originates from the strong oxidation capability,abundant active sites exposed and efficient charge transfer. More importantly, visible light irradiation gives rise to a prominent improvement of the OER performance, reducing the OER overpotential and Tafel slope by 140 m V and 28 m V dec^-1, respectively, demonstrating the striking photo-responsive OER activity of Cl-doped g-C3N4 nanorings. The great photo-induced improvement in OER activity would be related to the efficient charge transfer and the·OH radicals arising spontaneously on CN-Cl100 catalyst upon light irradiation. This work establishes Cl-doped g-C3N4 nanorings as a highly competitive metal-free candidate for photoelectrochemical energy conversion and environmental cleaning application.

关键词： Cl-doped g-C3N4 Nanoring Electrocatalysts Oxygen evolution reaction Pollutant degradation

Hierarchical Self-assembly of Well-Defined Louver-Like P-Doped Carbon Nitride Nanowire Arrays with Highly Effcient Hydrogen Evolution

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Nano-Micro Letters 2020年第4期12卷 76-91页

作者： Bo Li Yuan Si Qian Fang Ying Shi wei‑qing huang Wangyu Hu Anlian Pan Xiaoxing Fan Gui‑Fang huang Department of Applied Physics College of Physics and Electronicsand College of Materials Science and Engineeringand State Key Laboratory of Chemo/Biosensing and ChemometricsCollege of Chemistry and Chemical EngineeringHunan UniversityChangsha 410082People’s Republic of China Department of Physics and Tsinghua‑Foxconn Nanotechnology Research Center Tsinghua UniversityBeijing 100084People’s Republic of China College of Physics Liaoning UniversityShenyang 110036People’s Republic of China

Self-assembled nanostructure arrays integrating the advantages of the intrinsic characters of nanostructure as well as the array stability are appealing in advanced ***,the precise bottom-up synthesis of nanostructure arrays without templates or substrates is quite challenging because of the general occurrence of homogeneous nucleation and the difficult manipulation of noncovalent ***,we first report the precisely manipulated synthesis of well-defined louver-like P-doped carbon nitride nanowire arrays(L-PCN)via a supramolecular self-assembly method by regulating the noncovalent interactions through hydrogen *** this strategy,CN nanowires align in the outer frame with the separation and spatial location achieving ultrastability and outstanding photoelectricity ***,this self-assembly L-PCN exhibits a superior visible light-driven hydrogen evolution activity of 1872.9μmol h^−1 g^−1,rendering a^25.6-fold enhancement compared to bulk CN,and high ***,an apparent quantum efficiency of 6.93%is achieved for hydrogen evolution at 420±15 *** experimental results and first-principles calculations demonstrate that the remarkable enhancement of photocatalytic activity of L-PCN can be attributed to the synergetic effect of structural topology and *** findings suggest that we are able to design particular hierarchical nanostructures with desirable performance using hydrogen-bond engineering.

关键词： Self-assembly Carbon nitride P-doped Nanowire arrays Hydrogen evolution

Strain and interfacial engineering to accelerate hydrogen evolution reaction of two-dimensional phosphorus carbide

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Chinese Physics B 2021年第2期30卷 449-456页

作者： Tao huang Yuan Si Hong-Yu Wu Li-Xin Xia Yu Lan wei-qing huang Wang-Yu Hu Gui-Fang huang Department of Applied Physics School of Physics and ElectronicsHunan UniversityChangsha 410082China Department of Physics Kashgar UniversityKashgar 844006China College of Physics and Electronic Engineering Hengyang Normal UniversityHengyang 421002China School of Materials Science and Engineering Hunan UniversityChangsha 410082China

Hydrogen,regarded as a promising energy carrier to alleviate the current energy crisis,can be generated from hydrogen evolution reaction(HER),whereas its efficiency is impeded by the activity of ***,effective strategies,such as strain and interfacial engineering,are imposed to tune the catalysis performance of novel two-dimensional(2D)phosphorus carbide(PC)layers using first-principle *** findings show that P site in pristine monolayer PC(ML-PC)exhibits higher HER performance than C ***,constructing bilayer PC sheet(BL-PC)can change the coordinate configuration of P atom to form 3-coordination-P atom(3-co-P)and 4-coordination-P atom(4-co-P),and the original activity of 3-co-P site is higher than the 4-co-P *** an external compressive strain is applied,the activity of the 4-co-P site is enhanced whereas the external strain can barely affect that of 3-co-P ***,the graphene substrate enhances the overall activity of the BL-PC because the graphene substrate optimizes the?GH*value of 4-co-P site,although it can barely affect the HER activity of 3-co-P site and *** desirable properties render 2 D PC-based material promising candidates for HER catalysts and shed light on the wide utilization in electrocatalysis.

关键词： phosphorus carbide hydrogen evolution reaction(HER) coordination configuration electrocatalysis first principle calculations

Exosomes from circ-Astn1-modified adipose-derived mesenchymal stem cells enhance wound healing through miR-138-5p/SIRT1/FOXO1 axis regulation

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World Journal of Stem Cells 2023年第5期15卷 476-489页

作者： Zhi Wang Cheng Feng Hao Liu Tian Meng wei-qing huang Ke-Xin Song You-Bin Wang Department of Plastic and Cosmetic Surgery Peking Union Medical College HospitalBeijing 100730China

BACKGROUND Wound healing impairment is a dysfunction induced by hyperglycemia and its effect on endothelial precursor cells(EPCs)in type 2 diabetes *** is increasing evidence showing that exosomes(Exos)derived from adipose-derived mesenchymal stem cells(ADSCs)exhibit the potential to improve endothelial cell function along with wound ***,the potential therapeutic mechanism by which ADSC Exos contribute to wound healing in diabetic mice remains *** To reveal the potential therapeutic mechanism of ADSC Exos in wound healing in diabetic *** Exos from ADSCs and fibroblasts were used for high-throughput RNA sequencing(RNA-Seq).ADSC-Exo-mediated healing of full-thickness skin wounds in a diabetic mouse model was *** employed EPCs to investigate the therapeutic function of Exos in cell damage and dysfunction caused by high glucose(HG).We utilized a luciferase reporter(LR)assay to analyze interactions among circular RNA astrotactin 1(circ-Astn1),sirtuin(SIRT)and miR-138-5p.A diabetic mouse model was used to verify the therapeutic effect of circ-Astn1 on Exo-mediated wound *** High-throughput RNA-Seq analysis showed that circ-Astn1 expression was increased in ADSC Exos compared with Exos from *** containing high concentrations of circ-Astn1 had enhanced therapeutic effects in restoring EPC function under HG conditions by promoting SIRT1 ***-Astn1 expression enhanced SIRT1 expression through miR-138-5p adsorption,which was validated by the LR assay along with bioinformatics *** containing high concentrations of circ-Astn1 had better therapeutic effects on wound healing in vivo compared to wild-type ADSC *** and immunohistochemical investigations suggested that circ-Astn1 enhanced angiopoiesis through Exo treatment of wounded skin as well as by suppressing apoptosis through promotion of SIRT1 and decreased forkhead box O1 *** Circ-Astn1 promo

关键词： Adipose-derived mesenchymal stem cells Circular RNA astrotactin 1 Diabetic Exosomes Angiogenesis

Effects of coke charging pattern on burden movement in COREX melter gasifier based on physical simulation

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Journal of Iron and Steel Research International 2022年第6期29卷 907-913页

作者： Li-hao Han Yue-hua Li Li-ning Han Yan-xia Liu wei-qing huang Lei Cao Su-ci Qi Xin Guan Jian-lu Yuan Department of Material Engineering Hebei College of Industry and TechnologyShijiazhuang 050091HebeiChina Department of Basic Course Teaching Hebei College of Industry and TechnologyShijiazhuang 050091HebeiChina First Rolling Mill Anyang Iron&Steel Co.Ltd.Anyang 455000HenanChina

A three-dimensional semicircle cold model of COREX melter gasifier(MG)was established,and the effects of coke charging pattern on burden movement were investigated by adopting this *** burden flow pattern of packed bed was measured with different coke charging amounts,coke charging positions,and coke *** results show that the solid flow pattern presents a change from straight line type to reverse U type and finally to W type in MG with traditional coke charging,while the burden flow pattern experiences the change from straight line type to W type with platform and finally W type under center coke charging,and the solid flow pattern presents a change from straight line type to W type with platform and finally W type under intermediate coke *** difference demonstrates that coke charging pattern affects the uniform descending in MG to some *** burden in the coke charging zone keeps a straight line *** matter what kind of coke charging pattern is adopted,the burden residence time is shortened with the increase in coke charging amount,and the vertex of deadman decreases obviously,which is conducive to the renewal of the *** appropriate coke charging amount and coke size should be well controlled at 8.7%and 5 mm,*** results are useful not only in developing further understanding of solid flow in MG but also in verifying different mathematical models,particularly the coupled discrete element method with computational fluid dynamics simulation which has been increasingly used in the literature.

关键词： COREX melter gasifier Coke charging pattern Burden movement Flow pattern Physical simulation

Design of an ultrasonic motor with multi-vibrators

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2016年第9期17卷 724-732页

作者： Chong LI Cun-yue LU Yi-xin MA Shi-yang LI wei-qing huang Department of Instrument Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China Precision Driving Lab Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

This paper presents and verifies a new idea for constructing an ultrasonic motor （USM）. The stator contains several vibrators fabricated by bonding piezoelectric ceramics （PZTs） to a metal base. When two alternating current （AC） voltages with a 90° phase difference are applied to the PZTs, longitudinal and bending modes are excited in the vibrator. The bending vibrations of the vibrators are stacked to form the torsional vibration of the stator, ultimately generating longitudinal-torsional composite vibration. Both vibrators and the stator are excited to the resonance state. A standing wave is formed by superposition of longitudinal and torsional modes. The proposed motor is an in-plane vibration motor because the vibrations of the stator are in the circumferential plane. The finite element method （FEM） is used to validate the feasibility of the proposed motor. The fabricated stator contains five vibrators. The tested resonance frequencies of longitudinal and torsional modes are 44.42 kHz and 43.83 kHz, respectively. The stall torque is 0.3 N＇m and no-load speed is 45 r/min. The highest efficiency is 30%. The applied driving voltage is 100 Vo.p （peak voltage） at 43.9 kHz. The designed motor is a parallel-actuated integral motor. It allows the vibrators to operate synchronously, and overcomes asynchronous issues that occur in traditional multi-vibrator motors.

关键词： Ultrasonic motor (USM) Standing wave In-plane vibration Multi-vibrator