Engineering Commons^™

Design And Development Of Transition Metal-Based Electrocatalysts For Environmentally Friendly And Efficient Hydrogen Evolution Reactions (Her), Navid Attarzadeh

Open Access Theses & Dissertations

Hydrogen fuel is a clean energy source primarily because it emits no carbon dioxide (CO2). Sustainable energy alternatives have attracted the scientific community and policymakers as concerns over global warming and depletion of fossil fuels have increased significantly. Substituting H2 gas as a primary source for our daily energy consumption under the guideline of the hydrogen economy concept has not progressed as anticipated because of inadequate efficiency associated with the generation (electrolyzer) and utilization (fuel cell) devices. However, there are challenges associated with hydrogen that must be overcome for it to become a truly sustainable and widespread energy source. The …

Electrochemical Syntheses Of Nanomaterials And Small Molecules For Electrolytic Hydrogen Production, Jia-Qi Wei, Xiao-Dong Chen, Shu-Zhou Li

Journal of Electrochemistry

Hydrogen is a clean, efficient, renewable energy resource and the most promising alternative to fossil fuels for future carbon-neutral energy supply. Therefore, sustainable hydrogen production is highly attractive and urgently demanded, especially via water electrolysis that has clean, abundant precursors and zero emission. However, current water electrolysis is hindered by the sluggish kinetics and low cost/energy efficiency of both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In this regard, electrochemical synthesis offers prospects to raise the efficiency and benefit of water electrolysis by fabricating advanced electrocatalysts and providing more efficient/value-adding co-electrolysis alternatives. It is an eco-friendly and facile …

Adjusting The Alloying Degree Of Pt3Zn To Improve Acid Oxygen Reduction Activity And Stability, Tian-En Zhang, Ya-Ni Yan, Jun-Ming Zhang, Xi-Ming Qu, Yan-Rong Li, Yan-Xia Jiang

Journal of Electrochemistry

Proton exchange membrane fuel cell (PEMFC) is a new type of energy device, a relatively excellent way to achieve carbon neutrality. However, due to the relatively slow reaction rate of oxygen reduction reaction (ORR) at the cathode, platinum (Pt) is the key material of the cathode catalyst. However, Pt is a kind of noble metal, and its high cost restricts the PEMFC commercialization process. At present, the main approach is to combine transition metals with Pt to prepare Pt-based alloys and to reduce the use of Pt. Pt-based alloys are excellent catalysts for ORR, improving both the activity and stability, …

Rational Design Of Highly Efficient Electrocatalysts Using Atomic Layer Deposition: From Nanoparticle To Single Atom, Junjie Li

Electronic Thesis and Dissertation Repository

Polymer electrolyte membrane fuel cells (PEMFCs) have been attracted significant attention due to their high energy efficiency. The electrocatalyst is one of the most important parts. However, state-of-the-art electrocatalysts suffer from several challenges, including 1) low stability under harsh working conditions; 2) low atomic utilization efficiency, especially for noble metals. This thesis, therefore, focuses on the design of highly efficient and stable electrocatalysts from nanoparticles down to single atoms using atomic layer deposition (ALD) and further understand the insight mechanisms.

Firstly, Pt nanoparticles are selectively deposited on the TiO₂ modified N-doped carbon nanotubes. The strong metal-support interactions between Pt …

Pd-Based Electrocatalysts For Oxygen Reduction And Ethanol Oxidation Reactions: Some Recent Insights Into Structures And Mechanisms, Zhi-Peng Wu, Chuan-Jian Zhong

Journal of Electrochemistry

The development of efficient electrocatalysts for applications in fuel cells, including proton-exchange membrane fuel cell (PEMFC) and direct ethanol fuel cell (DEFC), has attracted extensive research attention in recent years. Oxygen reduction reaction and ethanol oxidation reaction are two of the key reactions where the design of active, stable and low-cost electrocatalysts is critical for the mass commercializations of PEMFCs and DEFCs. This challenge stems largely from the limited understanding of the catalyst structures and reaction mechanisms. Progress has been made in investigations of electrocatalysts derived from Pd-based alloy nanomaterials both experimentally and computationally. We highlight herein some of the …

Recent Advances In Graphene-Based Materials For Fuel Cell Applications, Hanrui Su, Yun Hang Hu

Michigan Tech Publications

The unique chemical and physical properties of graphene and its derivatives (graphene oxide, heteroatom-doped graphene, and functionalized graphene) have stimulated tremendous efforts and made significant progress in fuel cell applications. This review focuses on the latest advances in the use of graphene-based materials in electrodes, electrolytes, and bipolar plates for fuel cells. The understanding of structure-activity relationships of metal-free heteroatom-doped graphene and graphene-supported catalysts was highlighted. The performances and advantages of graphene-based materials in membranes and bipolar plates were summarized. We also outlined the challenges and perspectives in using graphene-based materials for fuel cell applications.

Electrochemical Preparations And Applications Of Nano-Catalysts With High-Index Facets, Chi Xiao, Na Tian, Zhi-You Zhou, Shi-Gang Sun

Journal of Electrochemistry

The performance of catalysts highly depends on their surface structure and composition. Nanocrystals bounded by high-index facets usually exhibit high catalytic activity due to their high-density low-coordinated step atoms with high reactivity. In this paper, we have reviewed the preparations of noble metals (e.g., Pt, Pd and Rh) nanocatalysts with high-index facets by electrochemical square-wave potential method developed in our group. The square-wave potential method includes a nucleation procedure to generate nuclei, followed by a square-wave potential procedure for a certain period of time for the growth of nuclei into nanocrystals. The formation mechanism of high-index facets is also discussed. …

Pd Nanoparticles Supported On The Etched Ni Foams As High-Performance Electrocatalysts For Direct Ethanol Fuel Cells, Chi Zhang, Cheng-Fei Li, Gao-Ren Li

Journal of Electrochemistry

The development of non-Pt anode electrocatalysts with high activity and long-term durability at low cost for fuel cells still remains enormous challenge. Here we report the Pd nanoparticles supported on Ni foams etched by the mixed acids (HNO₃+H₂SO₄+H₃PO₄+CH₃COOH) (Pd/ME-NF) that are designed and fabricated as high-performance electrocatalysts for ethanol oxidation in alkaline media. Because of the advantages of large open space, fast electrolyte penetration/diffusion and rapid electron transfer process, the Pd/ME-NF catalysts exhibited significantly improved electrocatalytic activity and durability compared with the commercial Pd/C catalysts.

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 …

N8- Polynitrogen Stabilized On Carbon-Based Supports As Metal-Free Electrocatalyst For Oxygen Reduction Reaction In Fuel Cells, Zhenhua Yao

Dissertations

The sluggish oxygen reduction reaction (ORR) kinetics at the cathode is one of the key factors limiting the performance of polymer electrolyte membrane fuel cell (PEMFC). Platinum-based materials are the most widely studied catalysts for this ORR reaction while their large-scale practical application in fuel cells is hindered due to their scarcity and low stability. Therefore, highly active, low cost and robust non-Pt catalysts are being developed to overcome the drawbacks. Recently, a novel polynitrogen N8- (PN) stabilized on multiwall carbon nanotube (MWNT) was synthesized under ambient condition for the first time by our group and demonstrated high ORR activities. …

Caging Porous Co-N-C Nanocomposites In 3d Graphene As Active And Aggregation-Resistant Electrocatalyst For Oxygen Reduction Reaction, Lu-Yang Xiu, Meng-Zhou Yu, Peng-Ju Yang, Zhi-Yu Wang, Jie-Shan Qiu

Journal of Electrochemistry

Oxygen reduction reaction (ORR) is the cornerstone reaction of many renewable energy technologies such as fuel cells and rechargeable metal-air batteries. The Pt-based electrocatalysts exhibit the highest activity toward ORR, but their large implementation is greatly prohibiting by unaffordable cost and inferior durability. During electrode manufacturing and electrochemical reaction, severe aggregation of catalyst nanoparticles induced by size effect further limits the operational performance of electrocatalysts. We report a new strategy for fabrication of active and aggregation-resistant ORR electrocatalyst by caging metal-organic frameworks derived Co-N-C nanocomposites in permeable and porous 3D graphene cages via sprayed drying the mixed colloids of ZIF-67 …

Facile Synthesis Of Nanostructured Metal Borides And Composites For Applications In Sustainable Energy, Maalavan Arivu

Masters Theses

"Electrocatalytic water splitting is a promising solution for sustainable energy generation since one of the half reactions lead to the formation of H₂ which is a clean fuel. The other half of the reaction leading to O₂ evolution is an energy intensive process necessitating the need for an electrocatalyst to break the activation barrier for the commencement of the reaction. In this work we will focus on expanding the family of non-oxidic OER electro-catalysts, especially borides, whereby, apart from facilitating delocalization of electron cloud on the catalytically active transition metal site, low anion electronegativity and increased covalency in …

Electroactivities Of Pd/Fe3O4-C Catalysts For Electro-Oxidation Of Methanol, Ethanol And Propanol, Tao Zou, Qing-Feng Yi, Yuan-Yuan Zhang, Xiao-Ping Liu, Guo-Rong Xu, Hui-Dong Nie, Xiu-Lin Zhou

Journal of Electrochemistry

Development of palladium (Pd) catalysts with high electroactivity for alcohol oxidation is significant for alcohol fuel cells. In this work, Pd nanoparticles were formed by sodium borohydride (NaBH₄) reduction method and subsequently deposited on the surface of carbon supported ferriferrous oxide (Fe₃O₄/C) composites to obtain the Pd/Fe₃O₄-C catalysts with different Fe₃O₄ loadings. Their transmission electron microscopic (TEM) images show that the Pd nanoparticles were uniformly dispersed on the Fe₃O₄/C. Electroactivities of the prepared Pd/Fe₃O₄-C catalysts toward oxidations of C1-C3 …

Comparative Studies Of Fe, Ni, Co And Their Bimetallic Nanoparticles For Electrochemical Water Oxidation, Maduraiveeran Govindhan, Brennan Mao, Aicheng Chen

Journal of Electrochemistry

The design of efficient, durable, and earth-abundant electrocatalysts via environmentally compatible strategies for the oxygen evolution reaction (OER) is a vital for energy conversion processes. Herein we report a facile approach for the fabrication of low-cost and earth abundant metal catalysts, including iron (Fe), nickel (Ni), cobalt (Co), CoNi, and CoFe nanoparticles (NPs) on titanium (Ti) substrates through a one-step electrochemical deposition. Field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) spectrocopy, X-ray photoelectron spectroscopy (XPS), and electrochemical techniques were employed to characterize these nanoparticles. Our electrochemical results revealed that among the five synthesized nanomaterials, the …

Platinum-Rhodium Alloy Electrocatalyst Activities In The Methanol Oxidation Reaction, William R. Sandorf

Williams Honors College, Honors Research Projects

This study evaluates the electrochemical activity of several compositions of platinum-rhodium alloys on carbon support to identify potential replacements for the expensive platinum electrocatalysts currently used in direct methanol fuel cells (DMFCs). The electrochemical active surface areas (ECSAs) of each sample were determined using cyclic voltammetry (CV) in a 0.5 M H₂SO₄ solution to normalize CV currents generated in the methanol oxidation reaction (MOR). The activity of five compositions was tested; Pt₃Rh, Pt₂Rh, PtRh, Pt₂Rh, and Pt₃Rh. 100 mg of each catalyst was synthesized at 10% by weight platinum …

Tungsten Carbide/Carbon Electrode Material Synthesized By Block Copolymer Template Method, Xiao-Ling Lang, Ye-Kun Jiang, Mei-Qin Shi, Ling-Zhi Kang, Chun-An Ma

Journal of Electrochemistry

At present, one of the major hurdles for commercialization of system with direct methanol fuel cell (DMFC) is still the requirement of a significant amount of platinum (Pt) catalyst to achieve an acceptable power density. Pt and Pt-based metals are expensive due to limited supplies. In order to find the catalyst alternative to the Pt metal, we selected tungsten carbide (WC) and its composites as the study object. We synthesized WC with carbon materials as the suitable support to modify the electronic structure and to increase the specific surface area of WC. In this study, tungsten carbide/carbon (WC/C) was prepared …

Vapor Synthesis And Thermal Evolution Of Supportless, Metal Nanotubes And Application As Electrocatalysts, Robert William Atkinson

Doctoral Dissertations

One of the major limitations of proton exchange membrane fuel cells (PEMFCs) is the high cost and poor durability of the currently preferred catalyst design, small Pt nanoparticles supported on high surface area carbon (Pt/C). Unsupported, high-aspect ratio nanostructured catalysts, or extended surface catalysts, are a promising paradigm as electrocatalysts for a number of electrochemical reactions. These extended surface catalysts generally exhibit higher specific activities compared to their carbon-supported nanoparticle counterparts that have been ascribed to their unique electronic, surface and structural properties. Extended surface catalysts frequently maintain enhanced durability over supported catalysts during fuel cell operation because they are …

Performance Of A Commercial Cathode-Supported Solid Oxide Fuel Cells Prepared By Single-Step Infiltration Of An Ion-Conducting Electrocatalyst, Xue Li, Nansheng Xu, Xuan Zhao, Kevin Huang

Kevin Huang

No abstract provided.

A Facile Approach To Synthesize Stable Cnts@Mno Electrocatalyst For High Energy Lithium Oxygen Batteries, Wenbin Luo, Shulei Chou, Jiazhao Wang, Yu-Chun Zhai, Hua-Kun Liu

Australian Institute for Innovative Materials - Papers

A composite of manganese monoxide loaded onto carbon nanotubes (CNTs@MnO) has been synthesized by a facile approach, in which the CNTs form a continuous conductive network connecting the electrocatalyst MnO nanoparticles together to facilitate good electrochemical performance. The electrocatalyst MnO shows favourable rechargeability, and good phase and morphology stability in lithium oxygen batteries. Excellent cycling performance is also demonstrated, in which the terminal voltage is higher than 2.4 V after 100 cycles at 0.4 mA cm^-2, with 1000 mAh g^-1 _(composite) capacity. Therefore, this hybrid material is promising for use as a cathode material for lithium oxygen …

N-Doped Crumpled Graphene Derived From Vapor Phase Deposition Of Ppy On Graphene Aerogel As An Efficient Oxygen Reduction Reaction Electrocatalyst, Meng Wang, Jiazhao Wang, Yuyang Hou, Dongqi Shi, David Wexler, Simon D. Poynton, Robert C.T. Slade, Weimin Zhang, Hua-Kun Liu, Jun Chen

Australian Institute for Innovative Materials - Papers

Nitrogen-doped crumpled graphene (NCG) is successfully synthesized via vapor phase deposition of polypyrrole onto graphene aerogel followed by thermal treatment. The NCG was explored as an electrocatalyst for the oxygen reduction reaction, showing comparable electrocatalytic performance with the commercial Pt/C in alkaline membrane exchange fuel cells because of the well-regulated nitrogen doping and the robust micro-3D crumpled porous nanostructure.

Ruo2 Nanorods As An Electrocatalyst For Proton Exchange Membrane Water Electrolysis, Richard Smith

Graduate College Dissertations and Theses

The desire for pure diatomic hydrogen gas, H2(g), has been on the rise since the concept of the hydrogen economy system was proposed back in 1970. The production of hydrogen has been extensively examined over 40 + years as the need to replace current fuel sources, hydrocarbons, has become more prevalent. Currently there are only two practical and renewable production methods of hydrogen; landfill gas and power to gas. This study focuses on the later method; using various renewable energy sources, such as photovoltaics, to provide off-peak energy to perform water electrolysis. Efficient electrolysis takes place in electrochemical cells which …

Synthesis Of Silver Nanoparticles Supported On Graphene Quantum Dots For Oxygen Reduction Reaction, Jian Ju, Wei Chen

Journal of Electrochemistry

Silver-based catalysts have been extensively investigated as the platinum substituted catalysts due to their high catalytic efficiency, low cost and long-term durability. In this study, the surfactant-free silver nanoparticles supported on graphene quantum dots were synthesized through a facile approach without addition of any other protecting ligands and reducing agents. The “surface-clean” silver nanoparticles had remarkable electrocatalytic performance towards oxygen reduction reaction (ORR) with the most efficient four-electron transfer process. Compared with commercial Pt/C catalyst, the hybrid nanoparticles showed comparable catalytic performance for ORR but much higher tolerance to methanol. Such silver nanoparticles supported on graphene quantum dots may have …

Performance And Durability Of Electrodes With Platinum Catalysts In Polymer Electrolyte Cells Prepared By Ultrasonic Spray Deposition, William A. Rigdon

Theses and Dissertations

Catalysts in the electrodes of polymer electrolyte cells serve a critical function in reactions which can be used to either generate electrical energy from chemical fuels or convert electrical energy into chemicals. For low temperature electrochemical fuel cells, platinum is often utilized for its exceptional catalytic activities towards hydrogen oxidation and oxygen reduction reactions of the anode and cathode, respectively. However, the limited supply of platinum and high demand result in prohibitive costs plaguing commercialization of this technology. Therefore, minimal amounts of the catalyst should be used to achieve the maximum output to reduce expenses. Electrochemical behavior is governed by …

Development Of Novel Nano-Structured Materials With Low-Cost And High Stability For Pem Fuel Cell, Dongsheng Geng

Electronic Thesis and Dissertation Repository

Polymer electrolyte membrane fuel cells (PEMFCs) are non-polluting and efficient energy conversion devices that are expected to play a dominant role in energy solutions of the future. However, due to high cost and known degradation issue of Pt electrocatalyst, more durable, efficient, and inexpensive electrocatalysts are required before fuel cells can become commercially viable. This research is revolving around the development of electrocatalysts such as non-noble metal oxygen reduction reaction (ORR) catalyst, new alternative supports, and novel Pt nanostructures to address the above-mentioned challenges in PEMFCs.

Firstly, we report the synthesis of nitrogen doped carbon nanotubes (CN_x) and …

Catalytic Activities Of Electrochemically Dealloyed Pt(Pd)-Cu Catalysts For Oxygen Reduction Reaction, Rui-Zhi Yang, Strasser Peter, Toney Michael

Journal of Electrochemistry

The electrochemically dealloyed Pt(Pd)-Cu catalysts were prepared by electrochemical dealloying of Cu3Pt(Pd) and their catalytic activities toward oxygen reduction reaction (ORR) were studied in 0.1 mol?L-1 HClO4 . solutions. The structural features of the dealloyed Pt(Pd)-Cu were revealed by synchrotron-based anomalous X-ray diffraction (AXRD) and surface X-ray scattering (SXS) at an atomic scale. We established a relationship between the structure and the catalytic activity by comparing the ORR activity and the structure of dealloyed Cu3Pt nanoparticles with similarly dealloyed Cu3Pt thin films and Cu3Pt(111). The enhancement in the activity of the dealloyed Pt(Pd)-Cu is mainly attributed to the strain change …

Multimetallic Electrocatalysts Of Pt, Ru, And Ir Supported On Anatase And Rutile Tio2 For Oxygen Evolution In An Acid Environment, Roderick E. Fuentes, Jake Farell, John W. Weidner

John W Weidner

Anatase and rutile TiO2 were investigated as stable supports for different multimetallic nanoparticles (i.e., Pt:Ru, Pt:Ir, Pt:Ru:Ir, and Ir:Ru) and tested for activity toward the oxygen evolution reaction (OER). Overall, Ir:Ru had the highest activity toward OER (i.e., current per gram of metal) compared to the other multimetallic combinations studied. This bimetallic supported on anatase TiO2 had a 53% higher current per gram of metal than an unsupported electrocatalyst of the same composition. The higher catalyst utilization of the supported electrocatalysts for OER is consistent with small, well-dispersed nanoparticles, which were observed in high resolution transmission electron microscopy images.

Development Of Novel Nanomaterials For High-Performance And Low-Cost Fuel Cell Applications, Shuhui Sun

Electronic Thesis and Dissertation Repository

Proton exchange membrane fuel cells (PEMFCs) are promising energy converting technologies to generate electricity by mainly using hydrogen as a fuel, producing water as the only exhaust. However, short life-time and high cost of Pt catalyst are the main obstacles for the commercialization of PEMFCs. In the conventional carbon black supported platinum nanoparticle (NP) commercial catalyst, carbon supports are prone to oxidation and corrosion over time that results in Pt NPs migration, coalescence, even detaching from the catalyst support. In addition, Ostwald ripening of the Pt NPs could also occur due to their high surface energy and zero dimensional structural …

Investigation Of Titanium Nitride As Catalyst Support Material And Development Of Durable Electrocatalysts For Proton Exchange Membrane Fuel Cells, Bharat Avasarala

Legacy Theses & Dissertations (2009 - 2024)

The impending energy and climatic crisis makes it imperative for human society to seek non-fossil based alternative sources for our energy needs. Although many alternative energy technologies are currently being developed, fuel cell technology provides energy solutions, which satisfy a wide range of applications. But the current fuel cell technology is far from its target of large scale commercialization mainly because of its high cost and poor durability. Considerable work has been done in reducing the cost but its durability still needs significant improvement. Of the various materials in a PEM fuel cell, the degradation of electrocatalyst affects its durability …

Multimetallic Electrocatalysts Of Pt, Ru, And Ir Supported On Anatase And Rutile Tio2 For Oxygen Evolution In An Acid Environment, Roderick E. Fuentes, Jake Farell, John W. Weidner

Faculty Publications

Anatase and rutile TiO2 were investigated as stable supports for different multimetallic nanoparticles (i.e., Pt:Ru, Pt:Ir, Pt:Ru:Ir, and Ir:Ru) and tested for activity toward the oxygen evolution reaction (OER). Overall, Ir:Ru had the highest activity toward OER (i.e., current per gram of metal) compared to the other multimetallic combinations studied. This bimetallic supported on anatase TiO2 had a 53% higher current per gram of metal than an unsupported electrocatalyst of the same composition. The higher catalyst utilization of the supported electrocatalysts for OER is consistent with small, well-dispersed nanoparticles, which were observed in high resolution transmission electron microscopy images.

Platinum Modified With Hydrogen Molybdenum/Tungsten Bronze As Electrocatalysts For Direct Small Organic Molecule Fuel Cell, Wei-Shan Li, Li-Peng Tian, Jun-Hua Du, Hong-Liang Huang, Wei Li, Li-Xia Zhang, Hong-Yan Yang, Pan-Pan Guo, Zhi-Hui Zhou, Xing-De Xiang, Zhao Fu

Journal of Electrochemistry

There are several problems that limit the application of direct small organic fuel cell,including the use of precious platinum and the activity loss of platinum due to the intermediates poisons from the oxidation of small organic molecules.These problems have attracted wide interest and many solutions have been proposed.We have developed a new method to reduce the platinum usage and improve its activity,based on the modification of platinum with hydrogen molybdenum/tungsten bronze(HxMo(W)O3,0