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Intermittent oxidation kinetics and metal/oxide interfacial undulation

Physical Review B 2024年第8期110卷 085402-085402页

作者： Dongxiang Wu Xianhu Sun Judith C. Yang Guangwen Zhou Department of Mechanical Engineering & Materials Science and Engineering Program Department of Chemical and Petroleum Engineering

The phenomenon of oxygen adsorption induced surface restructuring is widespread across various metal-oxygen systems, yet its impact on initiating bulk oxide formation remains largely unexplored. Through in situ atomic-resolution electron microscopy observations of surface oxidation of Cu(110) and Cu85Au15(110), we unveil intermittent oxide-film growth modulated by oxygen-induced surface restructuring. This modulation is evidenced by repeated pinning of the Cu2O growth front at isolated Cu columns of the c(6×2)-O reconstruction, owing to required long-range diffusion of Cu and O atoms to the Cu2O growth front. We reveal that Cu vacancies, generated at the Cu2O growth front, are injected into the Cu2O/Cu interface, inducing hill and valley undulation of the Cu2O film. In contrast, atomic vacancies produced during the Cu85Au15(110) oxidation preferentially migrate into interfaces between Au-rich and Au-poor regions in the bulk, resulting in a flat and adherent Cu2O film. These findings demonstrate the critical role of oxygen-induced surface restructuring in modulating oxide film growth kinetics and the manipulability of the fate of injected vacancies by alloying, thereby offering insights applicable to a broader range of metal-oxygen systems for fine-tuning oxidation kinetics and enhancing oxide/metal interfacial adhesion.

关键词： Surface & interfacial phenomena Surface reconstruction Surface growth Density functional theory Transmission electron microscopy

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Strain Softening of Styrene-Isoprene-Styrene Copolymers under Large Amplitude Oscillatory Shear for Clarifying Payne Effect in Rubbers and Their Nanocomposites

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Chinese Journal of polymer science 2023年第1期41卷 153-165页

作者： Xin-Peng Fan Yi-Hu Song Qiang Zheng Wan-Jie Wang MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhou310027China Shanxi-Zheda Institute of New Materials and Chemical Engineering Taiyuan030000China College of Materials Science and Engineering Henan Key Laboratory of Advanced Nylon Materials and ApplicationZhengzhou UniversityZhengzhou450001China

To illustrate mechanisms of Payne effect in rubbers and their nanocomposites experiencing large amplitude oscillatory shear(LAOS),comparison studies were performed in styrene-isoprene-styrene(SIS)copolymers and their selectively crosslinked materials at temperatures below and above glass transition temperature of the polystyrene(PS)*** was found that under periodic dynamic shear,the strain softening is reversible when the polyisoprene(PI)phase,either crosslinked or not,is restricted by hard PS domains but it shows hysteresis once the PS domains *** strain softening can happen at the time scale of intrinsic Rouse relaxation of elastically active network *** stress of strain softening scales with number density of elastically active network strands,a simple relation being verified not only in the selectively crosslinked SIS copolymers but also in PI gum vulcanizates and carbon black filled PI *** effect is traditionally used to term strain softening of highly filled rubber vulcanizates under LAOS deformation while evidenced herein is that the Payne effect of highly filled rubber vulcanizates shares the mechanism being common to the strain softening of SIS copolymers.

关键词： Large amplitude oscillatory shear SIS Rubber nanocomposites Strain softening

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Two-dimensional RGO-bridge S-scheme phosphorus-doped g-C_(3)N_(4)/Bi_(5)O_(7)Ivan der Waals heterojunctions for efficient visible-light photocatalytic treatment of real pharmaceutical wastewater

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science China(Technological sciences) 2023年第10期66卷 3011-3024页

作者： WANG ZhenZhou XU XiWei DENG Fang DIONYSIOU Dionysios D LI XiBao PENG JunLong LUO XuBiao ZOU JianPing LUO ShengLian National-Local Joint Engineering Research Center of Heavy Metal Pollutants Control and Resource Utilization Nanchang Hangkong UniversityNanchang 330063China Environmental Engineering and Science Program Department of Chemical and Environmental Engineering(DChEE)University of CincinnatiCincinnati 45221-0012USA

The design of van der Waals heterojunctions with S-scheme charge transfer pathway is expected to be an effective strategy for improvement of photocatalytic ***,two-dimensional(2D)phosphorus-doped g-C_(3)N_(4)/Bi_(5)O_(7)Ivan der Waals heterojunctions with reduced graphene oxide as electron bridge(PCN/RGO/Bi_(5O)_(7)I)were successfully synthesized via hydrothermal *** van der Waals interaction endowed 2D PCN/RGO/Bi_(5O)_(7)I with intimate contact interface,lattice match,tunable band structure,and internal electric field,which efficiently promoted interfacial charge separation and enhanced redox ability of photogenerated charge *** a result,the S-scheme PCN/RGO/Bi_5O_7I van der Waals heterojunctions exhibited superior photocatalytic performance in ciprofloxacin degradation and real pharmaceutical wastewater *** optimized 12%PCN/RGO/Bi_5O_7I displayed the highest photocatalytic activity with 92%removal of ***,the COD removal efficiency and extent of mineralization of real pharmaceutical wastewater reached 66.9%and 59.8%,respectively,and the biodegradability of pharmaceutical wastewater was significantly *** photocatalytic mechanism of the S-scheme PCN/RGO/Bi_(5)O_(7)I van der Waals heterojunctions based on the analysis of reactive species,work function,and internal electric field was *** study provides fresh insights into plausible design of S-scheme van der Waals heterojunction to enhance photocatalytic redox ability.

关键词： S-scheme heterojunction van der Waals heterostructure photocatalytic degradation ciprofloxacin energy consumption

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Rheological and stability analysis of cement pastes incorporating silica-based wastes

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Particuology 2024年第6期89卷 144-152页

作者： Julia da Rosa Martins Janaíde Cavalcante Rocha Dachamir Hotza Luciano Senff Graduate Program in Materials Science and Engineering(PPGMAT) Federal University of Santa Catarina(UFSC)Florianópolis88040-900SCBrazil Graduate Program in Civil Engineering(PPGEC) Federal University of Santa Catarina(UFSC)Florianópolis88040-900SCBrazil Graduate Program in Chemical Engineering(POSENQ) Federal University of Santa Catarina(UFSC)Florianópolis88040-900SCBrazil Department of Mobility Engineering Federal University of Santa Catarina(UFSC)Joinville89219-600SCBrazil

This study investigates the influence of waste characteristics,especially zeta potential,on the properties of cement pastes and *** focus is to evaluate the impact of the zeta potential of cement particles and waste materials on the sedimentation speed,rheology,and hardening time of stabilized cement *** Cement II F 40,retarder additive,silica,and fly ash were used in the *** pastes were prepared,and during the stabilization period,their rheological properties and pH were *** zeta potential and sedimentation speed of the cement and waste particles were measured at the pH that the pastes presented during the entire stabilization *** the stabilization period,the pastes were subjected to the hardening time *** zeta potential analyses revealed diverse values for the different powder types,with the cement particles exhibiting a zeta potential of−3.0 mV,the silica particles exhibiting−10.5 mV,and the fly ash particles exhibiting−20.3 *** influence of the high zeta potential modulus was observed on the sedimentation speed,with the solution containing fly ash exhibiting a speed of 40.01μm/s,whereas the solution containing only cement exhibited a speed of 99.38μm/*** the pastes,the results indicate that the presence of fly ash particles with a significantly negative zeta potential led to a 16%reduction in hardening time compared to particles with a lower modulus of zeta *** tests showed that the inclusion of fly ash particles prevented the formation of *** the zeta potential influenced agglomerate formation and hardening time,it was found to have no effect on yield stress or viscosity.

关键词： Wastes Zeta potential Setting time Rheometry

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Elucidating the roles of oxygen defects-rich TiO_xN_y shell in Ti-based electrocatalyst for enhanced oxygen reduction reaction

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Fundamental Research 2025年第3期5卷 1134-1143页

作者： Zhu, Xiaohang Zhao, Zongtao Tang, Jialiu Peng, Xuan Um, Han-Don Li, Xiaopeng Xiao, Qi Luo, Wei State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and Engineering Donghua University Shanghai 201620 China Department of Chemical Engineering Kangwon National University Gangwon Chuncheon 24341 South Korea

Ti-based materials are among the most widely studied catalysts for the oxygen reduction reaction (ORR). However, the actual roles of the catalytically active sites in N-doped Ti-based electrocatalysts are still unclear. In this work, TiO₂ and TiN were used as the precursors for the thermal nitridation and oxidation reactions at high temperatures, respectively. Titanium oxynitride (TiO_xN_y) species with abundant oxygen defects, formed on the surface of the as-prepared catalysts, were found to play an essential role to achieve the uniform distribution of ultrafine Pt nanoparticles via atomic layer deposition, thereby enhancing the ORR performance. The TiN-supported Pt catalyst showed excellent ORR performance and stability in acidic conditions, with an onset potential of 0.88 V and a half-wave potential of 0.76 V (vs. RHE). The catalyst also delivered a mass activity of 112 A g_Pt ⁻¹, which is 1.9 times higher than that of commercial Pt/C. A combination of experiments and characterizations confirmed that the synergistic effects between the outer TiO_xN_y shell with abundant oxygen defects and the high-conductivity TiN core contribute to the enhanced ORR performance. The present work sheds light on the essential roles of oxygen defect-rich TiO_xN_y species in Ti-based electrocatalysts. © 2023

关键词： Active sites Atomic layer deposition Core-shell structure Oxygen defects Oxygen reduction reaction Titanium oxynitride

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Reversal of circularly polarized luminescence direction and an“onoff”switch driven by exchange between UV light irradiation and the applied direct current electric field

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science China Chemistry 2022年第10期65卷 1945-1952页

作者： Kun Yao Zheng Liu Hang Li Dan Xu Wen-Hua Zheng Yi-Wu Quan Yi-Xiang Cheng Jiangsu Key Laboratory of Advanced Organic Materials School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China Key Laboratory of High Performance Polymer Material and Technology of Ministry of Education Department of Polymer Science and EngineeringSchool of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China

We report the rational design of a dual stimulus-activated quaternary chiral emission nematic liquid crystals(Q-N*-LCs)containing light-driven chiral dopant R-S-R-1,a static chiral dopant S-2 and an achiral Nile Red(NR)in a nematic liquid crystal(SLC1717).The dopant R-S-R-1 acts as a dynamic chiral donor and an energy donor,and the achiral NR serves as a circularly polarized luminescence(CPL)emitter and energy ***,this kind of Q-N*-LCs appears reversal CPL emission direction(L-CPL)using 365 nm UV light irradiation compared with the initial state(R-CPL).Most importantly,the“On-Off”CPL switch behavior of Q-N*-LCs can be repeatedly driven by revoking or rearranging the applied direct current(DC)electric *** OR chiral information logic gate demonstrates that this dual driven Q-N*-LCs can be potentially used for chiral information storage and coding.

关键词： chiral supramolecular liquid crystals circularly polarized luminescence light and electricity dual stimuli-activated Förster resonance energy transfer

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Non-thermal plasma-catalytic processes for CO2 conversion toward circular economy: fundamentals, current status, and future challenges

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Environmental science and Pollution Research 2024年 1-21页

作者： Mukhtar, Ahmad Saqib, Sidra Mohotti, Dinithi Ndeddy Aka, Robinson Jr. Hossain, Mokter Agyekum-Oduro, Ekow Wu, Sarah Department of Chemical and Biological Engineering University of Idaho MoscowID83843 United States Environmental Science Program University of Idaho MoscowID83844 United States

Practical and energy-efficient carbon dioxide (CO2) conversion to value-added and fuel-graded products and transitioning from fossil fuels are promising ways to cope with climate change and to enable the circular economy. The carbon circular economy aims to capture, utilize, and minimize CO2 emissions as much as possible. To cope with the thermodynamic stability and highly endothermic nature of CO2 conversion via conventional thermochemical process, the potential application of non-thermal plasma (NTP) with the catalyst, i.e., the hybrid plasma catalysis process to achieve the synergistic effects, in most cases, seems to promise alternatives under non-equilibrium conditions. This review focuses on the NTP fundamentals and comparison with conventional technologies. A critical review has been conducted on the CO2 reduction with water (H2O), methane (CH4) reduction with CO2 to syngas (CO + H2), CO2 dissociation to carbon monoxide (CO), CO2 hydrogenation, CO2 conversion to organic acids, and one-step CO2–CH4 reforming to the liquid chemicals. Finally, future challenges are discussed comprehensively, indicating that plasma catalysis has immense investigative areas. © The Author(s) 2024.

关键词： Circular economy

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Strengthening absorption ability of Co-N-C as efficient bifunctional oxygen catalyst by modulating the d band center using MoC

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Green Energy & Environment 2023年第2期8卷 459-469页

作者： Jianwen Liu Ying Guo Xian-Zhu Fu Jing-Li Luo Chunyi Zhi Shenzhen Key Laboratory of Polymer Science and Technology Guangdong Research Center for Interfacial Engineering of Functional MaterialsCollege of Materials Science and EngineeringShenzhen University518060China Department of Materials Science and Engineering City University of Hong Kong83 Tat Chee AvenueKowloon TongHong KongChina Department of Chemical and Materials Engineering University of AlbertaEdmontonAlbertaT6G 1H9Canada

Co-N-C is a promising oxygen electrochemical catalyst due to its high stability and good ***,due to the limited adsorption ability improvement for oxygen-containing intermediates,it usually exhibits inadequate catalytic activity with 2-electron pathway and high selectivity of hydrogen ***,the adsorption of Co-N-C to these intermediates is modulated by constructing heterostructures using transition metals and their derivatives based on d-band *** heterostructured nanobelts with MoC core and pomegranate-like carbon shell consisting of Co nanoparticles and N dopant(MoC/Co-N-C)are engineered to successfully modulate the d band center of active Co-N-C sites,resulting in a remarkably enhanced electrocatalysis *** optimally performing MoC/Co-N-C exhibits outstanding bi-catalytic activity and stability for the oxygen electrochemistry,featuring a high wave-half potential of 0.865 V for the oxygen reduction reaction(ORR)and low overpotential of 370 mV for the oxygen evolution reaction(OER)at 10 mA cm^(-2).The zinc air batteries with the MoC/Co-N-C catalyst demonstrate a large power density of 180 mW cm^(-2)and a long cycling lifespan(2000 cycles).The density functional theory calculations with Hubbard correction(DFT+U)reveal the electron transferring from Co to Mo atoms that effectively modulate the d band center of the active Co sites and achieve optimum adsorption ability with"single site double adsorption"mode.

关键词： Bifunctional oxygen catalysts Pomegranate-like shell D band theory Enhanced synergistic effect Rechargeable zinc air battery

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Lightweight foam-like nitrogen-doped carbon nanotube complex achieving highly efficient electromagnetic wave absorption

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Journal of Materials science & Technology 2024年第1期168卷 114-123页

作者： Zongcheng Li Jin Liang Zhiheng Wei Xin Cao Jiahui Shan Chunwei Li Xiaoyi Chen Dong Zhou Ruizhe Xing Chunjia Luo Jie Kong MOE Key Lab of Materials Physics and Chemistry in Extraordinary Conditions Shaanxi Key Laboratory of Macromolecular Science and TechnologySchool of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Key laboratory of Flexible Electronics of Zhejiang Province Ningbo Institute of Northwestern Polytechnical UniversityNingbo 315103China Polymer Materials and Engineering Department School of Materials Science and EngineeringChang’an UniversityXi’an 710064China

With the increased electromagnetic wave(EMW)threat to military and human health,the develop-ment of EMW-absorbing materials is ***-organic framework derivatives containing magnetic nanoparticles and a carbon matrix are potential candidates for designing efficient EMW-absorbing ***,a zeolitic imidazolate framework-67(ZIF-67)-embedded three-dimensional melamine foam is pyrolyzed to afford carbon foam-based nitrogen-doped carbon nanotube composites,named 3D foam-like CoO/Co/*** CoO/Co particles are confined in the dielectric carbon nanotube *** carbon nanotubes provide considerable conductive loss,while CoO/Co magnetic particles are con-ducive to providing magnetic loss and adjusting impedance ***,the numerous defect structures introduced by heteroatomic doping(nitrogen)cause dipole polarization and simultaneously adjust impedance ***,the unique porous nanotube structure promotes multiple re-flections and scattering of EMWs,further optimizing impedance ***/Co/N-CNTs composites exhibit a minimum reflection loss of−52.3 dB at a matching thickness of 2.0 mm,while the correspond-ing effective absorption bandwidth is 5.28 GHz at a matching thickness of 2.2 *** study reports a novel approach to fabricating a lightweight high-performance EMW-absorbing material.

关键词： Lightweight porous carbon materials Carbon nanotubes CoO/Co magnetic particles Electromagnetic synergistic effect Impedance matching

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A homologous strategy to parallelly construct doped MOFs-derived electrodes for flexible solid-state hybrid supercapacitors

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Nano Research 2023年第8期16卷 10890-10898页

作者： Yi-Lin Liu Ling Wang Qingyi Zeng Qi Kang Cheng Yan College of Mechanical Engineering University of South ChinaHengyang 421001China School of Materials Science and Engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China Department of Polymer Science and Engineering Shanghai Key Laboratory of Electrical Insulation and Thermal AgeingSchool of Chemistry and Chemical EngineeringShanghai Jiao Tong UniversityShanghai 200240China School of Chemistry Faculty of ScienceThe University of SydneySydney 2006Australia

Developing efficient and cost-effective electrode materials is of essential significance to advance various energy storage technologies,among which flexible supercapacitors hold great promise to meet the growing popularity of wearable ***,we report a homologous strategy to parallelly synthesize phosphorus-doped ZnCo_(2)O_(4)(P-ZnCo_(2)O_(4)@NCC)and nitrogen-doped carbon(NC@NCC)both derived from ZnCo-metal-organic frameworks(MOFs)precursors in-situ grown on dopamine-modified carbon cloth(NCC)as conductive ***,the as-obtained P-ZnCo_(2)O_(4)@NCC can achieve a high specific capacitance of 2702.2 mF∙cm^(−2)at 1 mA∙cm^(−2)with the capacitance retention rate exceeding 70.6%at 10 mA∙cm^(−2),demonstrating the outstanding rate ***,flexible solid-state hybrid supercapacitors,using P-ZnCo_(2)O_(4)@NCC as positive electrode and NC@NCC as negative electrode,are assembled with poly(vinyl alcohol)(PVA)/KOH as the gel electrolyte,which deliver the energy density of 11.9 mWh∙cm^(−3)when the power density reaches up to 47.3 mW∙cm^(−3).In addition,85.15%of the initial specific capacitance is maintained after 5000 continuous cycles and no obvious capacitance decay is observed under different bending conditions,revealing the excellent cycling stability and *** a proof-of-concept demonstration,two as-assembled hybrid supercapacitors connected in series can light up a red light-emitting diode(LED)under the bending angle of 180°,heralding the feasibility for broad practical applications.

关键词： homologous synthesis heteroatom-doping metal-organic frameworks energy storage flexible solid-state devices

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