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Articles 5221 - 5250 of 16385

Full-Text Articles in Materials Science and Engineering

Impact Of Fillers For Acrylic Compositions On Their Stability In Aggressive Mediums And Adhesive Strength, Liudmyla Trykoz, Svetlana Kamchatnaya, Oksana Pustovoitova, Inna Saiapina, Dmytro Borodin Sep 2020

Impact Of Fillers For Acrylic Compositions On Their Stability In Aggressive Mediums And Adhesive Strength, Liudmyla Trykoz, Svetlana Kamchatnaya, Oksana Pustovoitova, Inna Saiapina, Dmytro Borodin

Journal of Metals, Materials and Minerals

This paper aims to reveal the change of diffusion coefficient and permeability of the acrylic composition with different types of fillers (such as cement, sand, mica, and talc) in the various aggressive mediums. Also, the adhesive strength was determined as the maximal stress caused by detaching metal plate from the surface of the concrete. To evaluate the stability of the compositions, the samples of the acrylic compositions were saturated with acid and alkali solutions during a certain time. Basing on the mass change, the coefficients of diffusion, sorption, and permeability were calculated. The sand filled acrylic composition showed the least …

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Tailoring And Remotely Switching Performance Of Ultrafiltration Membranes By Magnetically Responsive Polymer Chains, Anh Vu, Arijit Sengupta, Emily Freeman, Xianghong Qian, Mathias Ulbricht, S. Ranil Wickramasinghe Sep 2020

Tailoring And Remotely Switching Performance Of Ultrafiltration Membranes By Magnetically Responsive Polymer Chains, Anh Vu, Arijit Sengupta, Emily Freeman, Xianghong Qian, Mathias Ulbricht, S. Ranil Wickramasinghe

Chemical Engineering Faculty Publications and Presentations

Magnetically responsive ultrafiltration membranes were prepared by grafting poly(2-hydroxyethyl methacrylate) chains from the outer surface of 100-kDa regenerated cellulose ultrafiltration membranes. Surface-initiated atom transfer radical polymerization was used to graft the polymer chains. Grafting from the internal pore surface was suppressed by using glycerol as a pore-filling solvent during initiator immobilization at varied densities. Glycerol suppresses the initiator attachment to the pore surface. Polymerization times of up to four hours were investigated. Superparamagnetic nanoparticles were covalently attached to the chain end. Membrane performance was determined using bovine serum albumin and dextran as model solutes. Increasing the grafted polymer chain density …

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Processing And Properties Of Medium-Mn Trip Steel To Obtain A Two-Stage Trip Behavior, D. M. Field, L. G. Garza-Martinez, D. C. Van Aken Sep 2020

Processing And Properties Of Medium-Mn Trip Steel To Obtain A Two-Stage Trip Behavior, D. M. Field, L. G. Garza-Martinez, D. C. Van Aken

Materials Science and Engineering Faculty Research & Creative Works

Two medium-Mn steels of nominal composition 0.15C-2.0Si-10.5Mn-(0.75, 1.5) Al-0.04Nb-balFe (wt pct) were processed to produce sub-micron grain sizes of 0.65 and 0.80 μm. Mechanical testing was performed in three successive conditions: hot rolled, intercritically annealed, and cold rolled with subsequent intercritical annealing. Intercritical annealing was performed at 923 K for 20 hours. Electron-backscattered diffraction and X-ray diffraction were utilized to characterize the microstructure, consisting of α-ferrite, α-martensite, ε-martensite, and γ-austenite. Microstructural constituents were tracked during tensile deformation, and it was found that both steels exhibited two-stage TRIP with γ-austenite martensitically transforming first to ε-martensite and as strain increased ε-martensite transformed …

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Development Of Zeolitic Imidazolate Frameworks For Enhancing Post-Combustion Co2 Capture, Dustin Lee Sep 2020

Development Of Zeolitic Imidazolate Frameworks For Enhancing Post-Combustion Co2 Capture, Dustin Lee

Master's Theses

Post-combustion CO2 capture is a promising approach for complementing other strategies to mitigate climate change. Liquid absorption is currently used to capture CO2 from post-combustion flue gases. However, the high energy cost required to regenerate the liquid absorbents is a major drawback for this process. As a result, solid sorbents have been investigated extensively in recent years as alternative media to capture CO2 from flue gases. For example, metal organic frameworks (MOFs) are nanoporous materials that have high surface areas, large pore volumes, and flexible designs. A large number of MOFs, however, suffer from 1) low CO …

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A Data-Driven Approach For Predicting Nepheline Crystallization In High-Level Waste Glasses, Irmak Sargin, Charmayne E. Lonergan, John D. Vienna, John S. Mccloy, Scott P. Beckman Sep 2020

A Data-Driven Approach For Predicting Nepheline Crystallization In High-Level Waste Glasses, Irmak Sargin, Charmayne E. Lonergan, John D. Vienna, John S. Mccloy, Scott P. Beckman

Materials Science and Engineering Faculty Research & Creative Works

High-level waste (HLW) glasses with high alumina content are prone to nepheline crystallization during the slow canister cooling that is experienced during large-scale production. Because of its detrimental effects on glass durability, nepheline (NaAlSiO4) precipitation must be avoided; however, developing robust, predictive models for nepheline crystallization behavior in compositionally complex HLW glasses is difficult. Using overly conservative constraints to predict nepheline formation can limit the waste loading to lower than the achievable capacity. In this study, a robust data-driven model using five compositional features has been developed to predict nepheline formation. A new descriptor is introduced called the …

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Chitosan Beads As The Adsorbent For Glyphosate Removal From An Aqueous Solution, Thanat Saelim, Sermpong Sairiam, Krisana Siralertmukul, Supawin Watcharamul, Roongkan Nuisin Sep 2020

Chitosan Beads As The Adsorbent For Glyphosate Removal From An Aqueous Solution, Thanat Saelim, Sermpong Sairiam, Krisana Siralertmukul, Supawin Watcharamul, Roongkan Nuisin

Journal of Metals, Materials and Minerals

Chitosan beads were prepared to remove glyphosate from an aqueous solution via a batch adsorption system. The optimum conditions, including initial glyphosateconcentration, adsorbent dose, and contact time, were investigated. Increasing the initial glyphosate concentration increased the equilibrium adsorption capacity onto the chitosan beads. The rapid sorption of glyphosate was found at an initial contact time of 30 min. The maximum adsorption capacity from 35 mg·L-1 glyphosate in solution onto 0.1 g chitosan beads was 12.7 mg·g-1. Increasing amount chitosan to 0.5 g dosage could remove more than 94% of the glyphosate for all initial glyphosate concentrations (1 - 35 mg·L-1), …

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Effects Of Quenchants On Microstructures And Mechanical Properties Ofsteel Gradeaisi 5160, Pattama Apichai Sep 2020

Effects Of Quenchants On Microstructures And Mechanical Properties Ofsteel Gradeaisi 5160, Pattama Apichai

Journal of Metals, Materials and Minerals

This research aims to study the effects of the quenchants in hardening process on microstructures and mechanical properties of alloy steel grade AISI 5160. The heat treatments include hardening at 900 (Q1), 870 (Q2), 840 (Q3), 810 (Q4) and 780°C (Q5),respectively, followed by quenching into water, oil and brine solution. Microstructures were measured scanning electron microscopy and energy dispersive X-ray spectroscopy.For each condition, hardness and tensile testing were measured. It was found that the microstructure in the as-sheetcondition consisted of ferrite and pearlite. The observed microstructures after quenching process were martensitewith a small amount of retained austainite. The hardening at …

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Optical Properties Of Tio2@Ag Nanowires And Nanospheres, Thananchai Dasri, Panuwat Chaiyachate, Sasiporn Audtarat, Panadda Charee, Artit Chingsungnoen Sep 2020

Optical Properties Of Tio2@Ag Nanowires And Nanospheres, Thananchai Dasri, Panuwat Chaiyachate, Sasiporn Audtarat, Panadda Charee, Artit Chingsungnoen

Journal of Metals, Materials and Minerals

Nanoparticles (NPs) with nonmetallic cores and metallic shells (such as Au, Ag, and Cu) can exhibit improve absorption efficiency due to localized surface plasmon resonance (LSPR), charge density oscillations at the surfaces of these core-shell composite nanoparticles. In this study, the effect of the geometry of TiO2@Ag core-shell composite nanoparticles on their optical absorption properties was theoretically illustrated in the wavelength ranges between the visible and infrared light regions of electromagnetic radiation. These nanostructures were modeled by varying the TiO2 core and Ag shell radii of the composite nanospheres and nanowires. The results indicate that varying the TiO2 core radius …

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Review On The Suppression Of Zn Dendrite For High Performance Of Zn Ion Battery, Jufni Abdulla, Jin Cao, Panyawat Wangyao, Jiaqian Qin Sep 2020

Review On The Suppression Of Zn Dendrite For High Performance Of Zn Ion Battery, Jufni Abdulla, Jin Cao, Panyawat Wangyao, Jiaqian Qin

Journal of Metals, Materials and Minerals

Researchers are paying more attention to the environmentally friendly and low-cost energy storage devices, due to the environmental issues and energy crisis caused by current commercial energy storage technologies. Zinc ion battery (ZIB) is one of the new, environment-friendly and low-cost energy storage technologies, which is the most promising alternative technology to replace the lithium ion battery applications. However, one of the challenges-dendrite growths during cycling of Zn anode is still limited its practical applications. In this review, the recent progress on suppression of Zn dendrite in various electrode design, electrolyte additives, and separator modifications for ZIBs is summarized.

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Incorporation Of Fe And Cu For Antibacterial Performance Enhancement Of Fe-Cu-Zno Nanocomposites Synthesized By A Facile Chemical Precipitation, Sucheewan Krobthong, Sutthipoj Wongrerkdee Sep 2020

Incorporation Of Fe And Cu For Antibacterial Performance Enhancement Of Fe-Cu-Zno Nanocomposites Synthesized By A Facile Chemical Precipitation, Sucheewan Krobthong, Sutthipoj Wongrerkdee

Journal of Metals, Materials and Minerals

Fe-Cu-ZnO nanocomposites were synthesized using simple chemical precipitation under a violent stirring condition, and characterized by dynamic light scattering, ultraviolet-visible spectroscopy, scanning electron microscopy, X-ray diffractometry, Raman spectroscopy, and vibrating sample magnetometer. The particle size distribution is observed not only a large size of 100 nm to 2 m, but also a small size of 0.4-5.0 nm. The absorbance peaks of the nanocomposites exhibit a small blue shift in comparison with ZnO. Surface defects are explored in the nanocomposites including irregular shapes, rough surfaces, and aggregation. The nanocomposites and ZnO have similar hexagonal wurtzite structures. However, the nanocomposites have more …

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Solid Particle Erosive Wear Behaviour Of Flame Sprayed Eva Based Polymeric Coatings, Ekrem Altuncu, Barış Önen Sep 2020

Solid Particle Erosive Wear Behaviour Of Flame Sprayed Eva Based Polymeric Coatings, Ekrem Altuncu, Barış Önen

Journal of Metals, Materials and Minerals

Flame spraying of polymers allows obtaining functional coatings for protecting against wear and corrosion. Among many engineering polymers, the Ethylene-Vinyl Acetate (EVA) copolymer attracts attention with its superior mechanical and chemical properties. EVA, which has high chemical resistance, high impact resistance and mechanical flexibility, high friction coefficient, is among the candidate coating material that can be used in aerospace, automotive, marine, chemical and manufacturing industries to protect metallic surfaces. The use of polymeric coatings in applications is often restricted when large surfaces need to be coated or if the coating needs to be applied in the openair field. Flame spraying …

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Experimental And Numerical Investigation Of The Influence Of Temperature On The Fracture Behavior Of High Impact Polystyrene Evaluated By The J-Integral Approach Using Multiple Specimen Method, Hanan El Bhilat, Abdelilah Hachim, Houda Salmi, Khalid El Had Sep 2020

Experimental And Numerical Investigation Of The Influence Of Temperature On The Fracture Behavior Of High Impact Polystyrene Evaluated By The J-Integral Approach Using Multiple Specimen Method, Hanan El Bhilat, Abdelilah Hachim, Houda Salmi, Khalid El Had

Journal of Metals, Materials and Minerals

The aim of the present work is to study the mechanical behavior in fracture of high impact polystyrene (HIPS) subjected to tensile tests under the effect of temperature to determine the R-curves. The theory of the J-integral contour has been used for the development of a characterization method of the fracture strength appropriate to the case of this non-linear elastoplastic polymer material. To this end, we used the method of multiple specimens (Single edge notch tension SENT) of thin thickness; we used several identical test pieces containing cracks of the same lengths. The tensile tests wereconducted under different temperatures, ranging …

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Microstructure Evolution And Mechanical Properties Of Calcined Kaolin Processing Waste-Based Geopolymers In The Presence Of Different Alkaliactivator Content By Pressing And Casting, Sitthisak Prasanphan, Anucha Wannagon, Takaomi Kobayashi, Sirithan Jiemsirilers Sep 2020

Microstructure Evolution And Mechanical Properties Of Calcined Kaolin Processing Waste-Based Geopolymers In The Presence Of Different Alkaliactivator Content By Pressing And Casting, Sitthisak Prasanphan, Anucha Wannagon, Takaomi Kobayashi, Sirithan Jiemsirilers

Journal of Metals, Materials and Minerals

In this work, microstructure evolution and mechanical properties of calcined kaolin processing waste-based geopolymers in the presence of low and high contents alkali activators were studied. Lower and higher contents of alkali activators were employed to synthesize geopolymers by pressing and casting methods, respectively. Chemicalbonding analysis, microstructure/elemental analysis, phase composition analysis, and compressive strength test were performed using FTIR, SEM/EDX, XRD, anduniversal mechanical testing machine, respectively. Findings showed that geopolymer with the low content of alkali activator formed by pressing (pressed geopolymer) might promote in the higher degree of geopolymerization because of higher compacted matrices but geopolymer with the high …

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Open-Source Grinding Machine For Compression Screw Manufacturing, Jacob Franz, Joshua M. Pearce Sep 2020

Open-Source Grinding Machine For Compression Screw Manufacturing, Jacob Franz, Joshua M. Pearce

Michigan Tech Publications, Part 1

Some of the most promising distributed recycling and additive manufacturing (DRAM) technical systems use fused particle fabrication (FPF) or fused granular fabrication (FGF), where compression screws force post-consumer waste plastic through a heated nozzle for direct 3D printing. To assist the technical evolution of these systems, this study provided the details of an invention for a low-cost, easily replicable open-source grinding machine for compression screw manufacturing. The system itself can be largely fabricated using FPF/FGF following the self-replicating rapid prototyper (RepRap) methodology. This grinding machine can be made from a cordless cut-off grinder and < $155 in parts. The new invention is demonstrated to be able to cut custom screws with variable (i) channel depths, (ii) screw diameters, (iii) screw lengths, (iv) pitches, (v) abrasive disk thicknesses, (vi) handedness of the screws, (vii) and materials (three types of steel tested: 1045 steel, 1144 steel, and 416 stainless steel). The results show that the device is more than capable of replicating commercial screws as well as providing makers with a much greater flexibility to make custom screws. This invention enables the DRAM toolchain to become even more self-sufficient, which assists the goals of the circular economy.

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Fatigue Of A Sic/Sic Ceramic Composite With An Ytterbium‐Disilicate Environmental Barrier Coating At Elevated Temperature, Marina B. Ruggles-Wrenn, Thaddeus M. Williams Sep 2020

Fatigue Of A Sic/Sic Ceramic Composite With An Ytterbium‐Disilicate Environmental Barrier Coating At Elevated Temperature, Marina B. Ruggles-Wrenn, Thaddeus M. Williams

Faculty Publications

Excerpt: Tension-tension fatigue performance of a SiC/SiC composite with an ytterbium-disilicate environmental barrier coating (EBC) was investigated at 1200°C in air and steam. The composite is reinforced with Hi-Nicalon™ SiC fibers and has a melt-infiltrated matrix processed by chemical vapor infiltration of SiC with subsequent infiltration with SiC particulate slurry and molten silicon. Abtract © American Ceramic Society

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Nonlinear Optical Measurements Of Cdsip2 At Near And Mid-Infrared Wavelengths, Manuel R. Ferdinandus, Jamie J. Gengler, Kent L. Averett, Kevin T. Zawilski, Peter G. Schunemann, Carl M. Liebig Sep 2020

Nonlinear Optical Measurements Of Cdsip2 At Near And Mid-Infrared Wavelengths, Manuel R. Ferdinandus, Jamie J. Gengler, Kent L. Averett, Kevin T. Zawilski, Peter G. Schunemann, Carl M. Liebig

Faculty Publications

We measure the birefringence of the nonlinear optical (NLO) properties of cadmium silicon phosphide via the Z-scan technique at near and mid-infrared wavelengths. We discuss the implications of the NLO properties on optical parametric amplifier performance. We find that the nonlinear absorption does reduce the conversion efficiency, while the nonlinear refraction has a negligible effect.

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Preparation And Characterisation Of Heat Treated Oil Palm-Empty Fruit Bunch/High Density Polyethylene Composites, Nordin Nur Afifah Sep 2020

Preparation And Characterisation Of Heat Treated Oil Palm-Empty Fruit Bunch/High Density Polyethylene Composites, Nordin Nur Afifah

Student Works (2020-2029)

Natural fibre composites (NFCs) are composite materials, in which the reinforcing fibres are derived from renewable and carbon dioxide neutral resources such as wood or plants. NFC can be made by replacing synthetic fibres with various types of natural fibres. Oil palm empty fruit bunch (OPEFB) fibre and oil palm mesocarp fibre are two important types of fibrous materials left in the palm-oil industry. In this study, EFB will be used as a reinforcement to the high-density polyethylene (HDPE). EFB was heat-treated at 180°C using vacuum oven for one hour, extrusion compounded with HDPE at 10%, 20% and 30% weight …

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Schottky And Poole-Frenkel Conduction Mechanisms In Zron/Sic System, Lusus Vanessa Sep 2020

Schottky And Poole-Frenkel Conduction Mechanisms In Zron/Sic System, Lusus Vanessa

Student Works (2020-2029)

In this work, the conduction mechanisms of Schottky Emission (SE) and Poole–Frenkel (PF) Emission for the ZrON/SiC system with a temperature range between 400 oC to 900 oC were analyzed. Understanding of the conduction charge mechanisms will help to estimate leakage characteristics of the ZrON/SiC system. Based on the J-E plot measured at different temperatures for 15 minutes, the obtained r2 was ranged between 0.90–0.98, which confirmed the data obtained complied with the standard SE model. Furthermore, the data plotted from the Effective Barrier Height Extracted from the SE plot showed the highest values of

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Optimized Transconductance Designs To Enhance The Linearity Performance Of Rf Front-End Receiver Circuits In 130 Nm Cmos Technology, Nandini Vitee Sep 2020

Optimized Transconductance Designs To Enhance The Linearity Performance Of Rf Front-End Receiver Circuits In 130 Nm Cmos Technology, Nandini Vitee

Student Works (2020-2029)

Highly linear front-end circuits are greatly desired for wireless receivers to improve the dynamic range. However, intermodulation distortions caused by the non-linear transconductor current limits the linearity of the front-end receiver circuit in CMOS technologies. In addition to the inherent nonlinear effect, the downscaling of CMOS further exacerbates the linearity of the circuit due to lower voltage headroom and high-field mobility. Thus, it is essential to develop effective circuit techniques that can aid linearity enhancement without jeopardizing other preferred performances such as low noise, high conversion gain, and low-power consumption. In this thesis, two different high linear transconductors are presented …

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Numerical Study Of Paraffin Wax Melting In A Cavity With A Gradient Of Hot Wall Inclination, Agus Dwi Korawan Aug 2020

Numerical Study Of Paraffin Wax Melting In A Cavity With A Gradient Of Hot Wall Inclination, Agus Dwi Korawan

Makara Journal of Technology

The melting of a phase change material (PCM) in a cavity with a gradient of hot wall inclination was simulated numerically using five models, namely, Model-A, Model-B, Model-C, Model-D, and Model-E with gradients of −2, −4, ∞, 4, and 2, respectively. The PCM was paraffin wax, which was melted using an enthalpy porosity technique with a pressure-based method. Model-A was found to be the best model. For the completion of the melting process, the models were assigned with the liquid fraction of 1. Model-A required the shortest time, followed by Model-B, Model-C, Model-E, and Model-D, respectively. Compared with Model-C, Model-A …

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Electrochemical Energy Storage And Conversion Based On Organic Electrodes, Jian-Hang Huang, Xiao-Li Dong, Zhao-Wei Guo, Yuan-Yuan Ma, Yan-Rong Wang, Yong-Gang Wang Aug 2020

Electrochemical Energy Storage And Conversion Based On Organic Electrodes, Jian-Hang Huang, Xiao-Li Dong, Zhao-Wei Guo, Yuan-Yuan Ma, Yan-Rong Wang, Yong-Gang Wang

Journal of Electrochemistry

Aqueous batteries have been considered to be a competitive candidate for large-scale energy storage. However, most of aqueous batteries adopt inorganic electrode materials with metallic elements, which are based on the reversible insertion of metal ions, making their application being highly hindered by limited cycle life, environmental issue, high cost and low reserves. On the other hand, organic electrode materials offer the advantages of abundant reserves, tunable structures, renewability and environmental benignity. Furthermore, the wide internal space enables these organics to flexibly store various charge carriers. Organics have been investigated as the alternative to inorganic electrode materials. Herein, we review …

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Research Progresses Of Copper Interconnection In Chips, Lei Jin, Jia-Qiang Yang, Fang-Zu Yang, Dong-Ping Zhan, Zhong-Qun Tian, Shao-Min Zhou Aug 2020

Research Progresses Of Copper Interconnection In Chips, Lei Jin, Jia-Qiang Yang, Fang-Zu Yang, Dong-Ping Zhan, Zhong-Qun Tian, Shao-Min Zhou

Journal of Electrochemistry

In this paper, the copper interconnection technology in chip manufacturing is introduced in detail, and the essentials of acidic copper sulfate electroplating process and the mechanisms of common-used additives are reviewed. The progresses of novel additives at home and abroad are also summarized. Based on the studied achievement, the possibility of the novel copper interconnect process replacing the acidic copper electroplating is prospected.

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Recent Progress In Bifunctional Catalysts For Zinc-Air Batteries, Neng-Neng Xu, Jin-Li Qiao Aug 2020

Recent Progress In Bifunctional Catalysts For Zinc-Air Batteries, Neng-Neng Xu, Jin-Li Qiao

Journal of Electrochemistry

Zinc-air battery has attracted great attention from researchers due to its high energy density and power density, which is expected to be widely used in energy conversion and storage. Air electrode as the core area of oxygen catalytic reaction is the focus of the entire zinc-air battery research. Recently, many research achievements have been made in non-noble metal bifunctional catalysts/electrodes with high activity, low cost and abundant species. In this review, we mainly focus on the reaction mechanism and the recent progress in non-noble metal oxide catalyst, carbon-based catalyst, and carbon-based transition metal compound composite and self-supporting electrode. In addition, …

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Recent Progress On Enhancing Effect Of Nanosized Metals For Electrochemical Co2 Reduction, Yu-Ning Zhang, Dong-Fang Niu, Shuo-Zhen Hu, Xin-Sheng Zhang Aug 2020

Recent Progress On Enhancing Effect Of Nanosized Metals For Electrochemical Co2 Reduction, Yu-Ning Zhang, Dong-Fang Niu, Shuo-Zhen Hu, Xin-Sheng Zhang

Journal of Electrochemistry

The electrochemical conversion of CO2 to chemical raw material for further utilization shows promising future to alleviate global warming and realize carbon cycle in nature, which is of great significance to the green chemistry and sustainable development. This review briefly introduces the advantages of CO2 electrochemical reduction (CO2ER) and its basic reaction principles, and summarizes the recent progress in a series of activity enhancement strategies based on nanosized metal catalysts. The influences of alloy effect, interface engineering, synergistic effect, surface defect engineering and support effect on the catalytic performance of nanosized metals for CO2ER …

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Research Progress Of Metal-Nitrogen-Carbon Catalysts Toward Oxygen Reduction Reaction Inm Changchun Institute Of Applied Chemistry, Ming-Jun Xu, Jie Liu, Jun-Jie Ge, Chang-Peng Liu, Wei Xing Aug 2020

Research Progress Of Metal-Nitrogen-Carbon Catalysts Toward Oxygen Reduction Reaction Inm Changchun Institute Of Applied Chemistry, Ming-Jun Xu, Jie Liu, Jun-Jie Ge, Chang-Peng Liu, Wei Xing

Journal of Electrochemistry

The development of highly active and stable catalysts toward oxygen reduction reaction (ORR) has been facing severe challenges. In recent years, pyrolytic M-N-C catalysts and metal-organic framework derived materials made the performance of non-noble metal catalysts greatly improved, however, the molecular and atomic level understanding in the reaction active sites and the mechanism are still lacking. Here, we summarize the recent research progress made in the Changchun Institute of Applied Chemistry. We present a microporous metal-organic-framework confined strategy toward the preferable formation of ORR catalysts. Firstly, we studied the active site and proposed a new active site structure for the …

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Electrochemical Carbon Dioxide Reduction In Flow Cells, Jia Fan, Na Han, Yan-Guang Li Aug 2020

Electrochemical Carbon Dioxide Reduction In Flow Cells, Jia Fan, Na Han, Yan-Guang Li

Journal of Electrochemistry

Electrochemical carbon dioxide reduction (CO2RR) is an appealing approach to convert atmospheric CO2 to value-added fuels and industrial chemicals, and may play an important role during the transition to a carbon-neutral economy. In order to make this technology commercially viable, it is essential to pursue CO2RR in flow reactors instead of conventional H-type reactors, and to combine electrocatalyst development with system engineering. In this review, we overview the cell configurations and performance advantages of the two types of flow reactors, analyze their shortcomings, and discuss the effects of their different components including gas diffusion electrode …

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Electrolyte Tailoring For Electrocatalytic Reduction Of Stable Molecules, Jin-Han Li, Fang-Yi Cheng Aug 2020

Electrolyte Tailoring For Electrocatalytic Reduction Of Stable Molecules, Jin-Han Li, Fang-Yi Cheng

Journal of Electrochemistry

Reduction of stable molecules such as CO2 and N2 is important process in electrochemical energy conversion and storage technologies for electrofuels production. However, for the inert nature of CO2/N2 molecule and competitive proton reduction in conventional aqueous electrolytes, selective electrochemical carbon/nitrogen fixation suffers from high overpotential, low reaction rate and low selectivity. While addressing these issues has witnessed substantial advances in electrocatalysts, much less attention has been placed on the electrolytes, which play an important role in regulating the local environment and thus the performance of catalysts under operating conditions. Rational design of electrolytes has …

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Fuel Cell Performance Of Non-Precious Metal Based Electrocatalysts, Yan-Feng Zhang, Fei Xiao, Guang-Yu Chen, Min-Hua Shao Aug 2020

Fuel Cell Performance Of Non-Precious Metal Based Electrocatalysts, Yan-Feng Zhang, Fei Xiao, Guang-Yu Chen, Min-Hua Shao

Journal of Electrochemistry

The commercialization of proton exchange membrane fuel cells (PEMFCs) is hindered by high cost and low durability of Pt based electrocatalysts. Developing efficient and durable non-precious metal catalysts is a promising approach to addressing these conundrums. Among them, transition metals dispersed in a nitrogen (N)-doped carbon support (M-N-C) show good oxygen reduction reaction activity. This article reviews recent progress in M-N-C catalysts development, focusing on the catalysts design, membrane electrode assembly fabrication, fuel cell performance, and durability testing. Template-assisted approach is an efficient way to synthesize M-N-C materials with homogeneously dispersed single atom active site and reduced metal particles, carbides …

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Divergence Of The Dielectric Constant In Ultrathin Granular Metal Films Near The Percolation Threshold, H. Bakkali, E. Blanco, Samuel Lofland, M. Dominguez Aug 2020

Divergence Of The Dielectric Constant In Ultrathin Granular Metal Films Near The Percolation Threshold, H. Bakkali, E. Blanco, Samuel Lofland, M. Dominguez

College of Science & Mathematics Departmental Research

We report on the electronic and optical properties of ultrathin granular films. We demonstrate that the static dielectric constant increases with thickness in the dielectric regime and diverges at the critical thickness, as predicted by classical percolation theory. However, for thicker samples, the dc conductivity does not obey scaling laws due to the presence of tunneling conduction. In this region the dielectric constant is positive, and the electronic transport is not metallic but can be described by Jonscher's universal power law, even though there is a Drude-like response indicating the presence of free charge carriers. Only for thicker films when …

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In Situ Electric-Field Study Of Surface Effects In Domain Engineered Pb(In1/2nb1/2)O3-Pb(Mg1/3nb2/3)O3-Pbtio3 Relaxor Crystals By Grazing Incidence Diffraction, Markys G. Cain, Margo Staruch, Paul Thompson, Christopher Lucas, Didier Wermeille, Yves Kayser, Burkhard Beckhoff, Samuel Lofland, Peter Finkel Aug 2020

In Situ Electric-Field Study Of Surface Effects In Domain Engineered Pb(In1/2nb1/2)O3-Pb(Mg1/3nb2/3)O3-Pbtio3 Relaxor Crystals By Grazing Incidence Diffraction, Markys G. Cain, Margo Staruch, Paul Thompson, Christopher Lucas, Didier Wermeille, Yves Kayser, Burkhard Beckhoff, Samuel Lofland, Peter Finkel

College of Science & Mathematics Departmental Research

In this work, we present a grazing incidence X-ray diffraction study of the surface of a 0.24Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) [011] poled rhombohedral single crystal. The near surface microstructure (the top several tens to hundreds of unit cells) was measured in situ under an applied electric field. The strains calculated from the change in lattice parameters have been compared to the macroscopic strain measured with a strain gauge affixed to the sample surface. The depth dependence of the electrostrain at the crystal surface was investigated as a function of temperature. The analysis revealed hidden sweet spots featuring unusually high strains that were …

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