Engineering Commons^™

Single-Layer Oxygen Deficiency Δ-Mno2 For Electrochemical Co2 Reduction, Yue-Feng Zhang, Jian-Jun Liu, Zeng-Xi Wei, Xin-Xin Tian, Jian-Min Ma

Journal of Electrochemistry

Manganese dioxide (MnO₂) has been widely used in catalysis. In addition, since the defect engineering can change the electronic properties of the catalyst, here we have systematically studied electrocatalytic carbon dioxide reduction reaction (CO₂RR) on δ-MnO₂ with and without oxygen deficiency, denoted as Ov-MnO₂ and MnO₂, respectively. We calculate the electronic properties and the intermediate of free energy for MnO₂ and Ov-MnO₂ with the help of spin-polarized density functional theory. By analyzing this result, we can find that the introduction of defects change the δ-MnO₂ from semiconducting properties to …

Statuses, Challenges And Strategies In The Development Of Low-Temperature Carbon Dioxide Electroreduction Technology, Xu-Rui Zhang, Xiao-Lin Shao, Jin Yi, Yu-Yu Liu, Jiu-Jun Zhang

Journal of Electrochemistry

Low-temperature carbon dioxide (CO₂) electrochemical reduction technology is a hotspot for research and development in recent years as a way to reduce the negative impact of CO₂ on the environment and to generate energy storage through converting electricity to low-carbon fuels. Although basic research on catalyst activity, product selectivity, and reaction mechanism has been widely reported, the design and practicality of catalytic stability and corresponding electrochemical reactor systems have not been given sufficient attention and systematic development.  In this paper, two important factors affecting the development of CO₂ electrochemical reduction technology in low temperature aqueous solution …

Recent Advances In Bismuth-Based Co2 Reduction Electrocatalysts, Rui Zhou, Na Han, Yan-Guang Li

Journal of Electrochemistry

Carbon dioxide (CO₂) is an economical, secure and sustainable carbon resource around us. Its effective capture and recycling have been the focus of our entire society. Using the electrochemical method, CO₂ can be reduced to different value-added chemicals or fuels. This approach not only would mitigate CO₂ accumulation in the atmosphere, but also would help alleviate our dependence on fossil fuel. In this article, the basic principle and process of electrochemical CO₂ reduction are first introduced. The recent development in bismuth-based catalysts for electrocatalytic CO₂ reduction is reviewed with an emphasis on their preparation, …

Electrocatalytic Reduction Of Carbon Dioxide To Carbon Monoxide Using Cobalt Nitride, Chen Ma, Peng-Fei Hou, Peng Kang

Journal of Electrochemistry

Electrocatalytic reduction of carbon dioxide (CO₂) is a promising method to alleviate global warming issues, although it still faces many challenges. Herein, we report cobalt nitride for electrocatalytic reduction of CO₂ to carbon monoxide (CO) in an aqueous electrolyte. A comparison of catalysts with different preparation temperatures and atmospheres suggests that nitrogen doping is critical to improve catalytic activity. For the most active catalyst of 700-Co_5.47N/C, the CO current density reached 9.78 mA·cm^-2 at potential of -0.7 V vs. RHE. In addition, the CO/H₂ ratio could be adjusted from 1:3 to 3:2 by …

Effect Of Morphology Of Fe-N Codoped Carbon Nanomaterial On Electrochemical Reduction Reactions, Er-Ling Li, Fa Yang, Ming-Bo Ruan, Ping Song, Wei-Lin Xu

Journal of Electrochemistry

Graphene nanosheets (GS) and carbon nanotubes have been considered as good catalysts candidates for applications in energy conversion and storage. However, hybrids of GS and carbon nanotubes are always formed in transition metal-based nitrogen-doped system, making the system quite complex for exploring the structure-activity relationship. To prepare the catalysts with desired species controllably, we try to adjust the outcomes with the effect of nitrogen on the growth of carbon nanotubes. In this work, a series of Fe-N co-doped carbon hybrid catalysts containing N-doped GS or hybrids of GS/bamboo carbon nanotubes (BCNTs) or BCNTs were obtained with one-step pyrolyzed method. To …

Electrochemical Detection Of 4-Nitrophenol Based On Glassy Carbon Electrode Modified By Tio2Nps/Rgo Composite, Lin-Na Jiu, Yong-Qiang Cheng

Journal of Electrochemistry

4-nitrophenol (4-NP) has become factitious pollution, and presented a serious threat to the nature and human health. It is necessary to develop a convenient and fast detection method. In this work, the glassy carbon electrode modified by titanium dioxide nanoparticles (TiO₂NPs)/reduced graphene oxide (RGO) composite as an electrochemical sensor was studied for the trace detection of 4-NP. The morphology of the composite was characterized by scanning electron microscopy (SEM). The homogeneous mixing of titanium dioxide nanoparticles and reduced graphene oxide increased the specific surface area of the composite, and facilitated the electrochemical reaction of 4-NP. The electrochemical characteristics …

Preparations And Electrocatalytic Properties Of Cu-Bipy-Btc-Derived Carbon-Based Catalyst For Oxygen Reduction Reaction, Li-Hua Zhang, Jun-Feng Chen, Wan-Tang Huang, Yong-You Hu, Jian-Hua Cheng, Yuan-Cai Chen

Journal of Electrochemistry

Efficient and low-cost oxygen reduction reaction (ORR) electrocatalyst plays a key role for fuel cells. In this paper, ORR active metal organic framework (MOF: Cu-bipy-BTC, bipy = 2,2?-bipyridine, BTC = 1,3,5-tricarboxylate) was prepared using hydrothermal method, and then carbon-based material MOF-800 was obtained from pyrolyzing Cu-bipy-BTC at 800 °C. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), nitrogen sorption isotherm and X-ray photolectron spectroscopy (XPS) were used to characterize the morphologies and structures of the catalysts. Linear sweep voltammetry (LSV) and current-time curve (i-t) were adopted to evaluate the electrocatalytic properties of the catalysts. The results …

Properties Of High Early-Strength Type V Cement Concrete For Rapid Repair, Nader Ghafoori, Matthew O. Maler, Meysam Najimi, Ariful Hasnat

Civil and Environmental Engineering and Construction Faculty Research

This study examines the suitability of ASTM Type V cement concrete for rapid repair applications. To this end, experimental results on transport and durability properties of high earlystrength concretes using ASTM Type V cement were compared with those of a more traditional cement used for rapid repair, i.e. Type III cement. A cement content of 445 kg/m3 (750 lb/yd3 ) was maintained for all studied concretes. The experimental program included compressive strength, absorption, rapid chloride migration, corrosion resistance, and mass loss due to freezing and thawing regimes. The results of this study revealed that use of Type III and V …

Preface To Special Issue Of Electrochemical Reduction Of Carbon Dioxide, Qing Li, Min Liu

Journal of Electrochemistry

No abstract provided.

Copper-Based Compounds For Electrochemical Reduction Of Carbon Dioxide, Fan Yang, Pei-Lin Deng, You-Jia Han, Pan Jing, Bao-Yu Xia

Journal of Electrochemistry

The electrochemical reduction of carbon dioxide (CO₂) to useful chemicals and fuels has attracted enormous interest since the deteriorating global warming and energy shortage problems resulted from ever-increasing CO₂ emission. Designing efficient catalysts is of capital significance to realize the efficient and selective conversion of CO₂. Among various catalysts explored, copper-based compounds have promising potentials with acceptable efficiency for hydrocarbon production. Herein, recent advances on copper-based materials are summarized for electrochemical CO₂ conversion. We intend to include the dimensional structure, different forms (alloy, oxide) and molecular catalysts in copper-based catalysts. Moreover, the reaction mechanisms …

Recent Progress In Copper-Based Catalysts For Electrochemical Co2 Reduction, Wen Lei, Wei-Ping Xiao, De-Li Wang

Journal of Electrochemistry

As the situation of energy crisis and environmental pollution become more and more serious, the electrochemical reduction of carbon dioxide (CO₂) has attracted lots of attention because of its multiple meanings such as environment, resources and economic benefits. In this paper, the state of the art electrochemical reduction of CO₂ in aqueous solution is reviewed, and the latest research progress in Cu-based catalysts with different structures and morphologies is summarized. In the end, the application prospects, opportunities and challenges of Cu-based materials are briefly presented to provide an outlook for future research directions.

Modifications Of The Cztse/Mo Back-Contact Interface By Plasma Treatments, Wenjin Chen, Teoman Taskesen, David Nowak, Ulf Mikolajczak, Mohamed H. Sayed, Devendra Pareek, Jorg Ohland, Thomas Schnabel, Erik Ahlswede, Dirk Hauschild, Lothar Weinhardt, Clemens Heske, Jurgen Parisi, Levent Gutay

Chemistry and Biochemistry Faculty Research

Molybdenum (Mo) is the most commonly used back-contact material for copper zinc tin selenide (CZTSe)-based thin-film solar cells. For most fabrication methods, an interfacial molybdenum diselenide (MoSe2) layer with an uncontrolled thickness is formed, ranging from a few tens of nm up to ≈1 μm. In order to improve the control of the back-contact interface in CZTSe solar cells, the formation of a MoSe2 layer with a homogeneous and defined thickness is necessary. In this study, we use plasma treatments on the as-grown Mo surface prior to the CZTSe absorber formation, which consists of the deposition of stacked metallic layers …

Abrasion Resistance Of High Early-Strength Concrete For Rapid Repair, Nader Ghafoori, Matthew O. Maler, Meysam Najimi, Ariful Hasnat

Civil and Environmental Engineering and Construction Faculty Research

This paper examines the abrasion resistance of high early-strength concrete developed for rapid repair of highways and bridge decks. The cement types chosen for this study included ASTM Type III, ASTM Type V, and Calcium Sulfoaluminate (CSA) cements. A cement content of 386 kg/m3 (650 lb/yd3 ) was maintained for all studied concretes. Test samples were tested after 24 hours and 28 days of curing in order to evaluate compressive strength and depth of wear. Test results revealed that the opening time to attain minimum required compressive strength for CSA cement concrete was one hour, whereas the values for Type …

Nanogaps On Atomically Thin Materials As Non-Volatile Read/Writable Memory Devices, Douglas Robert Strachan, Abhishek Sundararajan, Mathias Joseph Boland

Physics and Astronomy Faculty Patents

The present invention relates to the presence of nanogaps across a metal dispersed over an atomically-thin material, such that the nanogap exposes the atomically-thin material. The resulting device offers an ultra-short gap with ballistic transport and demonstrated switching in the presence of a gate or dielectric material in close proximity to the channel.

Rheological Properties Of Modified Crumb Rubber Asphalt Binder And Selecting The Best Modified Binder Using Ahp Method, Mehdi Khalili, Kazem Jadidi, Moses Karakouzian, Serji Amirkhanian

Civil and Environmental Engineering and Construction Faculty Research

Crumb rubber modifier (CRM) is one of the most popular asphalt binder modifiers due to the economic benefits and desired physical and rheological properties of asphalt binders and asphalt mixes. This research focuses on evaluating the properties of rubber-modified asphalt binders and selecting the best modified binder. The modified binders were produced by blending virgin binders with CRM at various contents of different gradations, and different methods of grinding. CRM made through ambient and cryogenic grinding methods with two gradation sizes were produced and tested. Three different virgin binders from two sources were obtained and used. The Analytic Hierarchy Process …

Computational And Experimental Approach To Understanding The Structural Interplay Of Self-Assembled End-Terminated Alkanethiolates On Gold Surfaces, Juganta K. Roy, Erick S. Vasquez, Henry P. Pinto, Swati Kumari, Keisha B. Walters, Jerzy Leszcynski

Chemical and Materials Engineering Faculty Publications

Applications of self-assembled monolayers (SAMs) on surfaces are prevalent in modern technologies and drives the need for a better understanding of the surface domain architecture of SAMs. To explore structural interaction at the interface between gold surfaces and a hydroxyl-terminated alkanethiol, 11-hydroxy-1-undecanethiol, (C11TH) we have employed a combined computational and experimental approach. Density functional theory (DFT) calculations were carried out on the thiol–gold interface using both the Perdew–Burke–Ernzerhof (PBE) and van der Waals (optB86b) density functionals. Our ab initio molecular dynamics (AIMD) simulations revealed that the interface consists of four different distinguished phases, each with different C11TH orientations. Experiments involved …

Processing Manipulation Of Carbon Content In Cu-34.6%Mn, Samuel Inman

The Journal of Purdue Undergraduate Research

No abstract provided.

Micrometeoroid Impacts On Periodic Spacecraft Structures, Victoria West, Luis Buades, Hanson-Lee Harjono

The Journal of Purdue Undergraduate Research

No abstract provided.

Atomistic Modeling Of Heat Treatment Processes For Tuning The Mechanical Properties Of Disordered Solids, Nikolai V. Priezjev

Mechanical and Materials Engineering Faculty Publications

We investigate the effect of a single heat treatment cycle on the potential energy states and mechanical properties of metallic glasses using molecular dynamics simulations. We consider the three-dimensional binary mixture, which was initially cooled with a computationally slow rate from the liquid state to the solid phase at a temperature well below the glass transition. It was found that a cycle of heating and cooling can relocate the glass to either rejuvenated or relaxed states, depending on the maximum temperature and the loading period. Thus, the lowest potential energy is attained after a cycle with the maximum temperature slightly …

The Potential Energy States And Mechanical Properties Of Thermally Cycled Binary Glasses, Nikolai V. Priezjev

Mechanical and Materials Engineering Faculty Publications

The influence of repeated thermal cycling on mechanical properties, structural relaxation, and evolution of the potential energy in binary glasses is investigated using molecular dynamics simulations. We consider a binary mixture with strongly non-additive cross interactions, which is annealed across the glass transition with different cooling rates and then exposed to one thousand thermal cycles at constant pressure. We found that during the first few hundred transient cycles, the potential energy minima after each cycle gradually decrease and the structural relaxation proceeds via collective, irreversible displacements of atoms. With increasing cycle number, the amplitudes of the volume and potential energy …

Comparison Of Fatigue Performance Between Additively Manufactured And Wrought 304l Stainless Steel Using A Novel Fatigue Test Setup, M. M. Parvez, Y. Chen, Joseph William Newkirk, Frank W. Liou

Materials Science and Engineering Faculty Research & Creative Works

In this research, a novel adaptive controlled fatigue testing machine was designed for bending type high cycle fatigue test. A unique dual gauge section Krouse type mini specimen was designed for simply supported transverse bending. Displacement controlled fatigue tests were implemented using an electromechanical actuator. The variation in the control signal and load observed during the test provides unique insights into realizing the deterioration of the specimen due to fatigue. These analyses were utilized to compare the fatigue performance of wrought and additively manufactured 304L stainless steel. The influence of the build direction on fatigue performance was also investigated by …

Effective Elastic Properties Of Additively Manufactured Metallic Lattice Structures: Unit-Cell Modeling, Okanmisope Fashanu, David Murphy, Myranda Spratt, Joseph William Newkirk, K. Chandrashekhara, Ben Brown, John Porter

Materials Science and Engineering Faculty Research & Creative Works

Lattice structures are lightweight materials, which exhibit a unique combination of properties such as air and water permeability, energy and acoustic absorption, low thermal conductivity, and electrical insulation. In this work, unit-cell homogenization was used to predict the effective elastic moduli of octet-truss (OT) lattice structures manufactured using selective laser melting (SLM). OT structures were manufactured using a Renishaw AM 250 SLM machine with various relative densities. Compression test was carried out at strain rate 5 x 10^-3 m^-1 using an MTS frame. Finite element analysis was used in the determination of the OT’s effective elastic properties. Results …

Compressive And Bending Performance Of Selectively Laser Melted Alsi10mg Structures, D. Murphy, O. Fashanu, Myranda Spratt, Joseph William Newkirk, K. Chandrashekhara, H. Misak, D. Klenosky

Materials Science and Engineering Faculty Research & Creative Works

Selective laser melting (SLM) is a widely used additive manufacturing technique that effectively manufactures complex geometries such as cellular structures. However, challenges such as anisotropy and mechanical property variation are commonly found due to process parameters. In a bid to utilize this method for the commercial production of cellular structures, it is important to understand the behavior of a material under different loading conditions. In this work, the behavior of additively manufactured AlSi10Mg under compression, bending, and tension loads was investigated. Vertical and horizontal build directions are compared for each type of loading. Specimens were manufactured using the reduced build …

Elevated Temperature Mechanical And Microstructural Characterization Of Slm Ss304l, G. R. Hecht, Sriram Praneeth Isanaka, Joseph William Newkirk

Materials Science and Engineering Faculty Research & Creative Works

SLM built SS304L was annealed and water quenched to minimize residual stress and avoid carbide precipitation. Mini-tensile characterization of strength and elongation at temperature conditions up to 800°C, along with observations of the associated microstructural transformations were utilized to understand the changes produced in SLM SS304L. As-built and annealed specimens were found to exhibit decreasing strength and elongation with increasing temperature as expected. Carbide precipitates appeared after short times at high temperatures within both as-built and annealed specimens for all cases, but no brittle intermetallic phase development was observed for any of the temperatures investigated. While the lack of Sigma, …

Optimizing The Valorization Of Industrial By-Products For The Induction Healing Of Asphalt Mixtures, Amir Tabakovic, Marta Vila-Cortavitarte, Daniel Jato-Espino, Daniel Castro-Fresno

Articles

Self-healing within asphalt pavements is the process whereby road cracks can be repaired automatically when thermal and mechanical conditions are met. To accelerate and improve this healing process, metal particles are added to asphalt mixtures. However, thisapproach is costly both in economic and environmental terms due to the use of virgin metallic particles. So, even though the self-healing of asphalt mixtures has been widely addressed in experimental terms over the years, there is a lack of research aimed at modelling this phenomenon, especially with the purpose of optimizing the use of metal particles through the valorization of industrial by-products. As …

Hydcem: A New Cement Hydration Model, Niall Holmes, Denis Kelliher, Mark Tyrer

Conference papers

Hydration models are useful to predict, understand and describe the behaviour of different cementitious-based systems. They are indispensable for undertaking long-term performance and service life predictions for existing and new products for generating quantitative data in the move towards more sustainable cements while optimising natural resources. One such application is the development of cement-based thermoelectric applications.

HYDCEM is a new model to predict the phase assemblage, degree of hydration, heat release and changes in pore solution chemistry over time for cements undergoing hydration for any w/c ratio and curing temperatures up to 450C. HYDCEM, written in MATLAB, is aimed at …

Evaluation Of Biodegradability Characteristics Of Cellulose-Based Film As Per Is/Iso 14855-1, Narayan C. Saha Dr, Gaurav Madhu Dr, Diksha B. Kadu Ms

Journal of Applied Packaging Research

Biodegradable polymers (especially those derived from plant sources) begin their lifecycle as renewable resources, usually in the form of starch or cellulose. In this paper, the evaluation of biodegradability of cellulose-based polymer film under controlled composting conditions as per the guidelines of IS/ISO 14855 (Part-1) standard has been described. Microcrystalline cellulose (MCC) powder was taken as positive-control polymer. The apparatus used to analyse the degree and rate of biodegradation was developed indigenously. The validation of the biodegradability testing apparatus was also performed as per the prescribed test method given in IS/ISO 14855-1.

Implementing Population-Based Mass Drug Administration For Malaria: Experience From A High Transmission Setting In North Eastern Uganda, Richard Elliott

Materials Science and Engineering Faculty Publications and Presentations

Background: Mass drug administration (MDA) is a suggested mean to accelerate efforts towards elimination and attainment of malaria-free status. There is limited evidence of suitable methods of implementing MDA programme to achieve a high coverage and compliance in low-income countries. The objective of this paper is to assess the impact of this MDA delivery strategy while using coverage measured as effective population in the community and population available.

Methods: Population-based MDA was implemented as a part of a larger program in a high transmission setting in Uganda. Four rounds of interventions were implemented over a period of 2 years at …

Investigation Of The Electrode Polarization Effect For Biosensor Applications, Anil Koklu

Mechanical Engineering Research Theses and Dissertations

My research focuses on electrokinetic transport. Particularly, in this dissertation, we focus on fabrication and testing of micro electrodes with nanostructured surfaces to minimize the electrode polarization (EP) effects for biosensor applications. In the first study, electrochemical deposition of gold nanoparticles on to planar gold electrodes was used to generate rough surfaces. Dendritic nanostructures that reduced EP up to two orders of magnitude was obtained by optimizing the deposition conditions. These structures also enhanced dielectrophoresis (DEP) response of our bio-chips, making them usable in physiological buffers. In further studies we discovered a universal scaling of EP in the frequency domain, …

Laboratory Evaluation Of Cold In-Place Recycling Asphalt Mixtures Using A Balanced Mix Design, Ahmed Saidi

Theses and Dissertations

The objective of this research study is to present a procedure for designing Cold In-Place Recycling (CIR) mixtures through balancing cracking and rutting for these mixtures. Eight CIR mixtures were prepared using two recycling agents (foamed and emulsified asphalts), then cured for three days at two temperatures (140oF and 50oF), and compacted at two gyration levels (30 and 70 gyrations). The CIR mixtures were prepared at constant dosages of water and cement, 3% and 1%, respectively. Air void of each CIR performance test specimen was determined using the CoreLok device. The rutting susceptibility of these mixtures was then evaluated using …