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Bridging molecular photosensitizer and catalyst on carbon nanotubes toward enhanced selectivity and durability for CO_(2)photoreduction

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Journal of Environmental Sciences 2024年第6期140卷 157-164页

作者： Xiaofeng Cui Xueting Wang Lijun Zhao Jixin Wang Tingting Kong Yujie Xiong Anhui Engineering Research Center of Carbon Neutrality The Key Laboratory of Functional Molecular SolidsMinistry of EducationAnhui Laboratory of Molecular-Based MaterialsCollege of Chemistry and Materials ScienceAnhui Normal UniversityWuhu 241002China School of Chemistry and Chemical Engineering Anqing Normal UniversityAnqing 246011China School of Chemistry and Materials Science University of Science and Technology of ChinaHefei 230026China

Homogenous molecular photocatalysts for CO_(2)reduction,especially metal complex-based photosensitizer-catalyst assemblages,have been attracting extensive research interests due to their efficiency and customizability.However,their low durability and recyclability limit practical applications.In this work,we immobilized the catalysts of metal terpyridyl complexes and the photosensitizer of[Ru(bpy)3]Cl2onto the surface of carbon nanotubes through covalent bonds and electrostatic interactions,respectively,transforming the homogeneous system into a heterogeneous one.Our characterizations prove that these metal complexes are well dispersed on CNTs with a high loading(ca.12 wt.%).Photocatalytic measurements reveal that catalytic activity is remarkably enhanced when the molecular catalysts are anchored,which is three times higher than that of homogeneous molecular catalysts.Moreover,when the photosensitizer of[Ru(bpy)3]Cl2is immobilized,the side reaction of hydrogen evolution is completely suppressed and the selectivity for CO production reaches 100%,with its durability also significantly improved.This work provides an effective pathway for constructing heterogeneous photocatalysts based on rational assembly of efficient molecular photosensitizers and catalysts.

关键词： durability selectivity catalyst

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Influence of Recycled Concrete Fine Powder on durability of Cement Mortar

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Fluid Dynamics & Materials Processing 2024年第1期20卷 45-58页

作者： Yadong Bian Xuan Qiu Jihui Zhao Zhong Li Jiana Ouyang School of Architectural and Civil Engineering Zhongyuan University of TechnologyZhengzhou450007China School of Civil Engineering Sun Yat-Sen University&Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai519082China

In this paper,the durability of cement mortar prepared with a recycled-concrete fine powder(RFP)was examined;including the analysis of a variety of aspects,such as the carbonization,sulfate attack and chloride ion erosion resistance.The results indicate that the influence of RFP on these three aspects is different.The carbonization depth after 30 days and the chloride diffusion coefficient of mortar containing 10%RFP decreased by 13.3%and 28.19%.With a further increase in the RFP content,interconnected pores formed between the RFP particles,leading to an acceleration of the penetration rate of CO_(2)and Cl^(−).When the RFP content was less than 50%,the corrosion resistance coefficient of the compressive strength of the mortar was 0.84-1.05 after 90 days of sulfate attack.But the expansion and cracking of the mortar was effectively alleviated due to decrease of the gypsum production.Scanning electron microscope(SEM)analysis has confirmed that 10%RFP contributes to the formation of a dense microstructure in the cement mortar.

关键词： Recycled concrete fine powder cement mortar carbonization sulfate chloride ion durability

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Dry Mix Slag—High-Calcium Fly Ash Binder. Part Two: durability

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Materials Sciences and Applications 2024年第3期15卷 37-51页

作者： Alexey Brykov Mikhail Voronkov Department of Chemical Technology of High-Melting Non-Metallic and Silicate Materials Saint Petersburg State Institute of Technology St. Petersburg Russia

This work investigates durability of cement-free mortars with a binder comprised of ground granulated blast furnace slag (GGBFS) activated by high-calcium fly ash (HCFA) and sodium carbonate (Na2CO3): the soundness, sulfate resistance, alkali-silica reactivity and efflorescence factors are considered. Results of tests show that such mortars are resistant to alkali-silica expansion. Mortars are also sulfate-resistant when the amount of HCFA in the complex binder is within a limit of 10 wt%. The fineness of fly ash determines its’ ability to activate GGBFS hydration, and influence soundness of the binder, early strength development, sulfate resistance and efflorescence behavior. The present article is a continuation of authors’ work, previously published in MSA, Vol. 14, 240-254.

关键词： Ground Granulated Blast-Furnace Slag High-Calcium Fly-Ash Sodium Car-bonate Blast-Furnace Slag Binder durability ASR Sulfate Attack Soundness Efflorescence

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Tuning electronic structure of RuO_(2)by single atom Zn and oxygen vacancies to boost oxygen evolution reaction in acidic medium

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Journal of Energy Chemistry 2024年第1期88卷 94-102,I0003页

作者： Qing Qin Tiantian Wang Zijian Li Guolin Zhang Haeseong Jang Liqiang Hou Yu Wang Min Gyu Kim Shangguo Liu Xien Liu College of Chemical Engineering Qingdao University of Science and TechnologyQingdao 266042ShandongChina Department of Chemistry City University of Hong KongHong Kong 999077China Department of Advanced Materials Engineering Chung-Ang UniversityAnseong-siGyeonggi-do 17546SeoulRepublic of Korea Beamline Research Division Pohang Accelerator Laboratory(PAL)Pohang 37673Gyeongsangbuk-doRepublic of Korea

The poor stability of RuO_(2)electrocatalysts has been the primary obstacles for their practical application in polymer electrolyte membrane electrolyzers.To dramatically enhance the durability of RuO_(2)to construct activity-stability trade-off model is full of significance but challenging.Herein,a single atom Zn stabilized RuO_(2)with enriched oxygen vacancies(SA Zn-RuO_(2))is developed as a promising alternative to iridium oxide for acidic oxygen evolution reaction(OER).Compared with commercial RuO_(2),the enhanced Ru–O bond strength of SA Zn-RuO_(2)by forming Zn-O-Ru local structure motif is favorable to stabilize surface Ru,while the electrons transferred from Zn single atoms to adjacent Ru atoms protects the Ru active sites from overoxidation.Simultaneously,the optimized surrounding electronic structure of Ru sites in SA ZnRuO_(2)decreases the adsorption energies of OER intermediates to reduce the reaction barrier.As a result,the representative SA Zn-RuO_(2)exhibits a low overpotential of 210 mV to achieve 10 mA cm^(-2)and a greatly enhanced durability than commercial RuO_(2).This work provides a promising dual-engineering strategy by coupling single atom doping and vacancy for the tradeoff of high activity and catalytic stability toward acidic OER.

关键词： Electrocatalyst Acidic oxygen evolution reaction Electronic structure engineering durability Reaction barrier

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Parametric investigation on the novel and cost-effective nano fly ash impregnated geopolymer system for sustainable construction

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Frontiers of Structural and Civil Engineering 2024年第2期18卷 170-183页

作者： R.MOHANA S.M.Leela BHARATHI Department of Civil Engineering Mepco Schlenk Engineering CollegeSivakasi 626123India

The hazardous environmental effects of greenhouse gas emissions and climate change demand alternative sources for cementitious materials in the construction industry.The development of geopolymer structures provides a way of producing 100%cement-free construction.In this research work,a novel and simple way of deriving nano particles from waste fly ash particles is promoted.The effect of adding the synthesized nano fly ash particles as a filler medium in geopolymer mortars was investigated by considering strength and durability properties.Parameter optimization was done by using regression analysis on the geopolymer mortar and the impact of adding nano fly ash particles was studied by varying different percentages of addition ranging from 0 to 7.5%by weight of binder content.From the results,it was observed that 1%nano fly ash acted not only as a filler but also as nano-sized precursors of the polymerization process,resulting in denser geopolymer medium.This can explain the extraordinary gain in strength of 72.11 MPa as well as the denser core with negligible level of chloride ion penetration,making the material suitable for the development of structures susceptible to marine environment.

关键词： geopolymer nano fly ash chloride ion penetration durability polymerization fillers

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Wetting-drying effect on the strength and microstructure of cementphosphogypsum stabilized soils

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 1049-1058页

作者： Lingling Zeng Xia Bian Jiaxing Weng Tao Zhang College of Civil Engineering Zhejiang University of TechnologyHanzhou310014China Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing210098China State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou221116China Jiangsu Water Source Company Ltd.of the Eastern Route of the South-to-North Water Diversion Project Nanjing210000China Power China Zhongnan Engineering Corporation Limited Changsha410027China

Phosphogypsum has often been used as an effective and environmentally friendly binder for partial replacement of cement,improving the engineering properties of slurries with high water content.However,the influence of phosphogypsum on the physicomechnical properties of stabilized soil subjected to wettingedrying cycles is not well understood to date.In this study,the effect of phosphogypsum on the durability of stabilized soil was studied by conducting a series of laboratory experiments,illustrating the changes in mass loss,pH value and unconfined compressive strength(qu)with wettingdrying cycles.The test results showed that the presence of phosphogypsum significantly restrained the mass loss in the early stage(lower than the 4th cycle),which in turn led to a higher qu of stabilized soil than that without phosphogypsum.After the 4th cycle,a sudden increase in mass loss was observed for stabilized soil with phosphogypsum,resulting in a significant drop in qu to a value lower than those without phosphogypsum at the 6th cycle.In addition,the qu of stabilized soils correlated well with the measured soil pH irrespective of phosphogypsum content for all wettingedrying tests.According to the microstructure observation via scanning electron microscope(SEM)and X-ray diffraction(XRD)tests,the mechanisms relating the sudden loss of qu for the stabilized soils with phosphogypsum after the 4th wetting-drying cycle are summarized as follows:(i)the disappearance of ettringite weakening the cementation bonding effect,(ii)the generation of a larger extent of microcrack,and(iii)a lower pH value,in comparison with the stabilized soil without phosphogypsum.

关键词： Wetting-drying Phosphogypsum Microstructure durability

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Solidification/Stabilization of Chromium in Red Mud-based Geopolymer

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Journal of Wuhan University of Technology(Materials Science) 2024年第4期39卷 819-830页

作者：田崇霏 LUO Zhongtao LIU Lei LIU Xiaohai 张美香陈萌 HAI Ran School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China Henan Renbang Technology Co. Ltd.Luoyang 471700China School of Water Conservancy and Civil Engineering Zhengzhou UniversityZhengzhou 450001China School of Architectural and Civil Engineering Zhongyuan University of TechnologyZhengzhou 450007China

Up to 1.5wt%of Cr(Ⅲ)salts(CrCl_(3),and Cr_(2)O_(3))and Cr(Ⅵ)salts(Na_(2)CrO_(4),and CaCr_(2)O_(7))were incorporated into red mud-based geopolymers,respectively.The solidification/stabilization,compressive strength,and durability of the Cr-containing geopolymers were investigated.The experimental results indicate that the red mud-based geopolymer could effectively solidify/stabilize different types of Cr salts with solidification/stabilization rates of above 99.61%.Geopolymers are environmentally safe when the dosage of CaCr_(2)O_(7)is≤1.0wt%,or the dosage of CrCl_(3),Cr_(2)O_(3),and Na_(2)CrO_(4)is≤1.5wt%,respectively.The effects of Cr salts on the compressive strength varies with the type and content of Cr salts.The freeze-thaw cycle is more destructive to geopolymer properties than sulfate attack or acid rain erosion.The solidification/stabilization of Cr is mainly attributed to the following reasons:a)The chemical binding of Cr is related to the formation of Cr-containing hydrates(eg,magnesiochromite((Mg,Fe)(Cr,Al)_(2)O_(4)))and doping into N-A-S-H gel and C-A-S-H gel framework;b)The physical effect is related to the encapsulation by the hydration products(e g,N-A-S-H gel and C-A-S-H gel).This study provides a reference for the treatment of hazardous Cr-containing wastes by solid waste-based geopolymers.

关键词： chromium solidification/stabilization geopolymer red mud durability

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Polyvinyl alcohol fiber cement-stabilized macadam:A review and performance evaluation

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第3期11卷 406-423页

作者： Chaohui Wang Jikang Liu Shaochang Chen Feng Chen Zhiwei Gao School of Highway Chang'an UniversityXi'an 710064China Shaanxi Transportation Technology Consulting Co. Ltd.Xi'an 710068China School of Information Engineering Xizang Minzu UniversityXianyang 712082China

This review evaluated research results on polyvinyl alcohol fiber cement-stabilized macadam(PVA-FCSM)to further improve the long-term durability of road structures and promote its in-depth study and high-quality application.The suitable PVA fiber technical indexes for ordinary cement-stabilized macadam(CSM)were recommended.The difference in the mechanical properties between CSM and PVA-FCSM was described.The extent to which PVA fibers enhance the durability of CSM were clarified.Additionally,the mechanism of enhancement of CSM by PVA fibers was revealed.Finally,the performance of each type of fiber cement-stabilized macadam(FCSM)was compared and evaluated.The results indicated that the suggested PVA fiber length and content for CSM were 12-30 mm and 0.6-1.2 kg/m^(3),respectively.At different ages,the mean degree of improvement in the unconfined compressive strength was 14%,20%,and 14%,that in the compressive resilience modulus was 8%,11%,and 6%,and that in the splitting strength was 29%,15%,and 22%,respectively.At different ages,the mean degree of decreased in the dry shrinkage coefficient was 21%,16%,and 15%and that in the temperature shrinkage coefficient(20℃-30℃)was 23%,23%,and 18%,respectively.The coefficients increased with extended curing age.Moreover,at the same stress level,PVA-FCSM has a higher fatigue life compared to CSM.The bridging effect,high strength,and high modulus of PVA fiber enhance the strength and anti-cracking of CSM.The recommended fiber type for CSM is PVA fiber.

关键词： Highway and railway engineering PVA fiber cement-stabilized macadam Mechanical performance durability Enhancement mechanism Performance valuation

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Ultrathin ternary PtNiGa nanowires for enhanced oxygen reduction reaction

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Chinese Chemical Letters 2024年第2期35卷 599-603页

作者： Giday Fisseha Yiping Hu Yanan Yu Shaojie Lu Dongsheng Ma Pei Nian Zheng Wang Qin Yue Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 610054China State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering School of Chemistry and Chemical EngineeringNingxia UniversityYinchuan 750021China

Achieving high activity and durability for the oxygen reduction reaction(ORR)with an ultra-low amount of platinum is significant to promote the widespread application of proton exchange membrane fuel cells(PEMFCs).Here we report a new ultrathin(∼1 nm)ternary PtNiGa alloy nanowires(PtNiGa NWs)electrocatalyst,in which the presence of gallium(Ga)enhances the oxidation resistance of platinum(Pt)and nickel(Ni)and suppresses the dissolution of Ni.The mass and specific activities of PtNiGa NWs are about 11.2 and 7.6 times higher than those of commercial Pt/C catalysts for ORR.Moreover,the mass activity of PtNiGa/C NWs nanocatalyst decreased only by 12.8%and largely retained its electrochemical surface area(ECSA)after 10,000 potential cycles,compared with 38%loss of ECSA for commercial Pt/C catalyst.Therefore,this work provides a general guideline for preparing ternary alloy electrocatalysts and enhancing the activity and stability of the cathode ORR reaction of PEMFCs.

关键词： Ultrathin nanowires Gallium Oxygen reduction reaction Ternary alloy durability

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Ultrasensitive Mechanical Sensor Using Tunable Ordered Array of Metallic and Insulating States in Vanadium Dioxide

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Chinese Physics Letters 2024年第7期41卷 74-86页

作者：马泽成闫胜楠陈繁强戴玉頔刘增霖徐康徐涛童湛钦陈墨雨王利铮王鹏飞孙立涛程斌梁世军缪峰 Institute of Brain-Inspired Intelligence National Laboratory of Solid State MicrostructuresSchool of PhysicsCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China SEU-FEI Nano-Pico Center Key Laboratory of MEMS of Ministry of EducationSoutheast UniversityNanjing 210096China Institute of Interdisciplinary of Physical Sciences School of ScienceNanjing University of Science and TechnologyNanjing 210094China

Detecting tiny deformations or vibrations, particularly those associated with strains below 1%, is essential in various technological applications. Traditional intrinsic materials, including metals and semiconductors, face challenges in simultaneously achieving initial metallic state and strain-induced insulating state, hindering the development of highly sensitive mechanical sensors. Here we report an ultrasensitive mechanical sensor based on a strain-induced tunable ordered array of metallic and insulating states in the single-crystal bronze-phase vanadium dioxide [VO_(2)(B)] quantum material. It is shown that the initial metallic state in the VO_(2)(B) flake can be tuned to the insulating state by applying a weak uniaxial tensile strain. Such a unique property gives rise to a record-high gauge factor of above 607970, surpassing previous values by an order of magnitude, with excellent linearity and mechanical resilience as well as durability. As a proof-of-concept application, we use our proposed mechanical sensor to demonstrate precise sensing of the micro piece, gentle airflows and water droplets. We attribute the superior performance of the sensor to the strain-induced continuous metal-insulator transition in the single-crystal VO_(2)(B) flake, evidenced by experimental and simulation results. Our findings highlight the potential of exploiting correlated quantum materials for next-generation ultrasensitive flexible mechanical sensors, addressing critical limitations in traditional materials.

关键词： metallic durability hinder

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