Chemistry Commons^™

Research Progresses In Polymeric Proton Exchange Membranes For Fuel Cells, Xu-Po Liu, Yun-Feng Zhang, Shao-Feng Deng, De-Li Wang, Han-Song Cheng

Journal of Electrochemistry

Proton exchange membrane (PEM) is one of the key components in PEM fuel cells, which possesses the function of separating the cathode and anode, affording proton transport channels and preventing fuel permeability. The property of PEM significantly influences the performance and service life of fuel cells. Nowadays, the commercially used Nafion membranes have the shortcomings of serious fuel permeability, low proton conductivity at elevated temperature and high price, which limits the rapid development of PEM fuel cells. Therefore, it seems to be urgent to develop novel PEMs with low cost and good comprehensive properties. Polymeric proton exchange membrane is an …

Preparations Of Nickel-Iron Hydroxide/Sulfide And Their Electrocatalytic Performances For Overall Water Splitting, Hang-Shuo Lu, Xiao-Bo He, Feng-Xiang Yin, Guo-Ru Li

Journal of Electrochemistry

The Ni-Fe/Ti oxygen evolution electrode was prepared by electrodeposition on a titanium mesh substrate. Then, the as prepared Ni-Fe/Ti electrode was used to derive the Ni-Fe-S/Ti hydrogen evolution electrode through solid phase sulfuration. The effects of the molar ratio of Ni²⁺ to Fe³⁺ in the electrolyte and the amount of thiourea on the structures and electrochemical performances of Ni-Fe/Ti and Ni-Fe-S/Ti electrodes were investigated. The results show that the oxygen evolution performance of Ni-Fe/Ti electrode was first increased and then decreased with the increase of nickel ion content in the electrolyte. The Ni9Fe1/Ti electrode exhibited the best oxygen …

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. …

Recent Progress In The Mechanistic Understanding Of Co2 Reduction On Copper, Matthew M Sartin, Wei Chen, Fan He, Yan-Xia Chen

Journal of Electrochemistry

In this review, we present the major developments in the understanding of the mechanisms of the electrochemical reduction of CO₂ from a historical perspective. Most of the work discussed in this review was carried out at copper electrodes, as this is the only material at which hydrocarbons are produced in reasonable quantities. The emphasis focuses on the differentiation of mechanisms for the generation of C1 and C2 products as well as factors and methods for controlling the product selectivity of CO₂ reduction. We have highlighted ambiguities, assumptions, and important methodologies, such as differential electrochemical mass spectrometry and electrochemical …

Effect Of Nitrogen Content In Catalyst Precursor On Activity Of Fen/C Catalyst For Oxygen Reduction Reaction, Zhi Yang, Ya-Yun Shen, E Zhou, Cheng-Ling Wei, Hao-Li Qin, Juan Tian

Journal of Electrochemistry

Non-noble metal catalysts with high activity and low cost have attracted increasing interest as potential catalysts for oxygen reduction reaction (ORR) to replace Pt-based catalysts. In this paper, the effect of nitrogen content in catalyst precursor on ORR activity of FeN/C catalyst was investigated by X-ray diffraction (XRD), Brunauer-Emmet-Teller (BET) surface area and pore size distribution measurements, transmission electron microscope (TEM), thermogravimetric analysis (TGA), and rotating disk electrode (RDE) techniques. The results show that the most active catalyst was obtained by pyrolysis in argon at 1050 °C with a catalyst precursor containing 20wt% 1,10-phenanthroline, 1wt% Fe and Black Pearl 2000. …

Nanoscale Colocalization Of Fluorogenic Probes Reveals The Role Of Oxygen Vacancies In The Photocatalytic Activity Of Tungsten Oxide Nanowires, Meikun Shen, Tianben Ding, Steven T. Hartman, Fudong Wang, Christina Krucylak, Zheyu Wang, Che Tan, Bo Yin, Rohan Mishra, Matthew D. Lew, Bryce Sadtler

Electrical & Systems Engineering Publications and Presentations

Defect engineering is a strategy that has been widely used to design active semiconductor photocatalysts. However, understanding the role of defects, such as oxygen vacancies, in controlling photocatalytic activity remains a challenge. Here, we report the use of chemically triggered fluorogenic probes to study the spatial distribution of active regions in individual tungsten oxide nanowires using super-resolution fluorescence microscopy. The nanowires show significant heterogeneity along their lengths for the photocatalytic generation of hydroxyl radicals. Through quantitative, coordinate-based colocalization of multiple probe molecules activated by the same nanowires, we demonstrate that the nanoscale regions most active for the photocatalytic generation of …

Ni-Au Anodic Nano-Electrocatalyst For Direct Glucose Fuel Cells, Islam M. Al-Akraa, Aya S. Abdulhalim Eng, Yassr M. Asal Mr, Ahmad M. Mohammad Prof

Chemical Engineering

This study aims at the sequential assembling of a nickel oxide (NiOx: cauliflower-like nanostructure, 90 nm) and gold (Au; spherical, 95 nm in an average particle size) onto the GC surface nanocatalyst on a glassy carbon (GC) electrode (will be abbreviated as Ni-Au/GC) for the glucose electro−oxidation (GO); the principal anodic reaction in the direct glucose fuel cells (DGFCs). The charge of the Ni deposition on the GC surface (will be abbreviated as Ni/GC electrode) was initially optimized to obtain the highest catalytic activity toward GO which attained at (339.8 Ag−1) by applying 15 mC in the Ni deposition. Yet, …

Tuning The Activity And Stability Of Platinum Nanoparticles Toward The Catalysis Of The Formic Acid Electrooxidation, Islam M. Al-Akraa, Bilquis A. Al-Qodami, Santosh Sridhar Mysore Dr, R. Viswanatha Dr, Abdul Kareem Thottoli, Ahmad M. Mohammad

Chemical Engineering

No abstract provided.

Enhanced Glucose Electrooxidation At Ni-Cu Binary Oxide Nanocatalyst, Islam M. Al-Akraa, Mahmoud M. Abouzaid Eng, Yaser M. Asal Mr, Ahmad M. Mohammad Prof

Chemical Engineering

The aim of this study is to fabricate a nickel (NiOx) and copper (CuOx) oxide nanocatalyst on a glassy carbon (GC) electrode (will be abbreviated as Ni-Cu/GC) for glucose oxidation (GO). A sequential electrodepositon mode was applied to assemble NiOx and CuOx in the fabrication scheme. The optimization of Ni loading on the GC surface (will be abbreviated as Ni/GC electrode) was achieved first to attain the maximum catalytic efficiency in terms of the specific current toward GO. This (409 Ag1)was obtained by applying 15 mC/cm2 in the deposition of Ni. However, unfortunately the NiOx/GC could not support a long-term …

Reactions At The Critical Point Of Solution, Jason Mote

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Effect Of The Electrodeposition Potential Of Platinum On The Catalytic Activity Of A Pt/Gc Catalyst Toward Formic Acid Electro−Oxidation, Islam M. Al-Akraa, Bilquis A. Al-Qodami Ms., Ahmad M. Mohammad Prof

Chemical Engineering

The electrocatalytic activity of platinum (Pt)–modified glassy carbon (GC) (referred as Pt/GC) electrodes toward the formic acid electro−oxidation (FAO) was investigated. The Pt deposition on the GC substrate was carried out by a potentiostatic technique at different potentials (from 0.2 V to −0.2 V vs. Hg/Hg2Cl2/KCl (sat.) reference electrode) and the corresponding influence on the catalytic activity toward FAO was monitored. The electrocatalytic inspection revealed a potential role for the Pt deposition potential in boosting the catalytic efficiency of the catalyst toward FAO and further in mitigating the CO poisoning that eventually deactivate the catalyst. Interestingly, the highest activity toward …

A Spin-Coated Tiox/Pt Nanolayered Anodic Catalyst For The Direct Formic Acid Fuel Cells, Islam M. Al-Akraa, Ahmad M. Mohammad Prof

Chemical Engineering

The CO poisoning of the platinum anodic catalyst which typically functions the catalytic deterioration of the direct formic acid fuel cells could be minimized with a simple modification for Pt with titanium oxide. The fabrication scheme involved the spin-coating of a Ti precursor onto a Pt thin layer that was physically sputtered onto a Si substrate. The whole assembly was subjected to a post-annealing processing to produce the TiOx layer (60 nm) in a porous structure (mostly Anatase) atop of the Pt surface. The porous nature of the TiOx layer permitted the participation of Pt in the electrocatalysis of the …

Effect Of Cocatalyst Combination In Titanium-Based Ziegler-Natta Catalyst On Olefin Polymerization, Thanyaporn Pongchan

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research focused on effect of cocatalyst types (TEA, TnOA, and TEA+TnOA) on titanium-based Ziegler-Natta catalyst in olefin polymerization both in slurry and gas-phase systems. This study has been divided into four sections. The commercial titanium-based catalyst was selected to investigate effect of reaction temperature and oxidation state of titanium from ESR measurement on slurry ethylene and propylene polymerization in the first and the second parts, respectively. The commercial catalyst with TEA exhibited the highest activity in ethylene polymerization. However, divalent, and trivalent of titanium (Ti2+ and Ti3+) was active in ethylene polymerization to produce more polymer. Stability of Ti3+ …

Structure, Morphology And Composition-Property Elucidation Of Ni–Mo And Ni−Mo−P Nanocrystals For Water Splitting Reactions And Group Iv Alloy And Silicate Nanocrystals For Visible To Near Ir Optoelectronics, Ebtesam Hassan Abuelenein Eladgham

Theses and Dissertations

Abstract

Structure, Morphology and Composition-Property Elucidation of Ni–Mo and Ni−Mo−P Nanocrystals for Water Splitting Reactions and Group IV Alloy and Silicate Nanocrystals for Visible to Near IR Optoelectronics

by

Ebtesam Hassan Abuelenein Eladgham

A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University.

Advisor: Indika U Arachchige

Associate Professor, Department of Chemistry

Nanomaterials have gained a great attention because of their unique physical properties with size intermediate between molecular materials and extended solids. They have a large surface to volume ratio and display size tunable physical properties that was not …

Ionic Liquid Assisted Synthesis Of Porous Carbons From Rice Husk For Supercapacitors, Han-Fang Zhang, Feng Wei, Jian Sun, Meng-Ying Jing, Xiao-Jun He

Journal of Electrochemistry

It is still a challenge to prepare carbon materials with high specific surface area at low cost from renewable resources. Herein, the authors report an efficient approach to synthesize porous carbons (PCs) from rice husk with ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF₆)) as a template and an activation agent. The as-made PCs featured the high specific surface area up to 1438 m²·g^-1. As electrodes for supercapacitors, PCs showed a high specific capacitance of 256 F·g^-1 at 0.05 A·g^-1 in 6 mol·L^-1 KOH aqueous electrolyte and a good rate performance of 211 F·g …

Transient Electrochemical Surface-Enhanced Raman Spectroscopic Study In Electrochemical Reduction Of P-Nitrothiophenol, Yun Ling, Jing Tang, Guo-Kun Liu, Cheng Zong

Journal of Electrochemistry

P-nitrothiophenol (PNTP) is one of the most common probe molecules studied by surface-enhanced Raman spectroscopy (SERS). The research in electrochemical reduction behavior of PNTP will help understanding the mechanism for the nitrobenzene reduction. In this paper, we used transient electrochemical surface-enhanced Raman spectroscopy (TEC-SERS) to study the SERS of PNTP with cyclic voltammetry and chronoamperometry on gold electrodes. The results show that the TEC-SERS provide a time resolution that equals the transient electrochemical methods, and we concluded that the reaction was so quick that we did not observe the spectral information of intermediate species described in the literatures with a …

Zif-67-Derived Ag/Co-Embedded N-Enriched Mesoporous Carbon For Oxygen Reduction Reaction, Zheng-Ling Di, Jing Zhu, Lei Dai, Wei Meng, Yue-Hua Li, Zhang-Xing He, Ling Wang

Journal of Electrochemistry

Nitrogen-doped porous carbon materials are considered as one of the most promising catalysts for oxygen reduction reaction (ORR). Herein, in order to further improve the activity of the nitrogen-doped porous carbon, Ag/Co bimetal is embedded into nitrogendoped porous carbon to form Ag/Co-embedded nitrogen-doped porous carbon material (AgCo@NC). The AgCo@NC was derived by the wet impregnation of Ag+ into ZIF-67 precursor, followed by chemical reduction and a subsequent pyrolysis process under Ar atmosphere at different temperatures (500 ℃, 600 ℃, 700 ℃). The morphologic characterization shows that the Ag/Co nanoparticles were successfully embedded in the mesoporous carbon framework with abundant nitrogen …

Electrochemical Sensor Based On Magnetic Electrode Modified With Magnetic Molecularly Imprinted Nanoparticles Immobilized Hemoglobin For Determination Of Hydrogen Peroxide, Yang Yuan, Jia-Xin Wang, Yu-Hua Cao

Journal of Electrochemistry

In this work, the surface-imprinted technique was used to prepare magnetic hemoglobin (Hb) imprinted nanoparticles, using Fe₃O₄@SiO₂ NPs as the carrier, Hb as the template molecule, and tetraethyl orthosilicate (TEOS) as the imprinted polymer monomer. The nanoparticles had a core-shell structure, with magnetic Fe₃O₄ NPs as the core and Hb imprinted polymers as the shell. Therefore, Hb could be concentrated and fixed on the surface of the magnetic imprinted nanoparticles (MMIPs NPs). Furthermore, MMIPs NPs were immobilized with chitosan (CS) on the surface of a magnetic electrode to constitute Hb enzyme-like biosensor …

Special Issue: Electrocatalysis And Fuel Cells, Shuangyin Wang

Journal of Electrochemistry

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A Facile Route To Synthesize Pt-Wo3 Nanosheets With Enhanced Electrochemical Performance For Her, Peng-Jie Jiang, Yi Lv, Chang-Miao Chen, Hong-Cheng He, Yong Cai, Ming Zhang

Journal of Electrochemistry

Platinum-tungsten trioxide (Pt-WO₃) nanosheets were synthesized on nickel foams (NFs) directly. As great conductive networks, NFs substrates could greatly improve the electrode performance of WO₃. The modified platinum nanoparticles not only enhanced the electron transformation of catalysts, but also increased the active sites for hydrogen evolution reaction (HER). Pt-WO₃/NF revealed a better catalytic activity than WO₃/NFs with a smaller Tafel slope (80 mV·dec^-1) and a lower overpotential of 72 mV at the current density of 10 mA·cm^-2. In addition, Pt-WO₃/NF showed great durability and stability during …

Three-Dimensional Porous Vn Octahedron Catalyst With High Electrocatalytic Efficiency Toward Hydrogen Evolution Reaction, Can Yin, Wei-Wei Fu, Ling Fang, Shi-Li You, Hui-Juan Zhang, Yu Wang

Journal of Electrochemistry

With the rapid development of China’s economy, the demand for energy is increasing, and environmental problems are becoming more and more serious. The development and utilization of highly-clean new energy fuel can effectively alleviate the energy crisis and environmental pollution. Nowadays, exploring high-efficiency, environment-friendly and low-cost catalysts remains the focus of research in the hydrogen evolution reaction (HER). In this research, firstly, we proposed a three-dimensional porous vanadium nitride (VN) with octahedral structure, which was prepared by a calcination treatment method. The VN catalyst showed a good electrocatalytic activity toward HER, involving a small overpotential of 94.0 mV at -10 …

Influences Of Morphology And Nitrogen Doping On The Electrocatalytic Characteristics For Oxygen Reduction Reaction Of Nio/Rgo, Dong Liang, Heng-Yi Fang, Shuo Yao, Jie-Mei Yu, Zhao-Liang Zhang, Zhan-Kun Jiang, Xue-Ping Gao, Tai-Zhong Huang

Journal of Electrochemistry

In this research, the reduced graphene oxide (rGO) supported sheet-like NiO (NiO/rGO) and spherical-like NiO (NiO/N-rGO) catalysts for oxygen reduction reaction (ORR) were prepared. The structures, morphologies and chemical states of the two catalysts were characterized by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical catalytic performance of the two catalysts for ORR were investigated by cyclic voltammetry (CV), Tafel, linear sweeping voltammetry (LSV), rotating disc electrode (RDE) and rotating ring disc electrode (RRDE) tests. Electrochemical results showed that the current density and onset potential (about 0.89 V) …

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.

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 …

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.

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 …

Regulation Of Copper Surface Via Redox Reactions For Enhancing Carbon Dioxide Electroreduction, Bao-Hua Hang, Jin-Tao Zhang

Journal of Electrochemistry

A large-scale application of fossil fuels has led to excessive emission of carbon dioxide (CO₂), resulting in serious environmental issues. A promising path to reducing CO₂ emissions is recycling CO₂ into valuable chemicals and fuels through an electrochemical process. Herein, the redox reactions between copper (Cu) and ferric chloride (FeCl₃) have been utilized to regulate the Cu surface composition and structure, aimed to improve the electrocatalytic activity toward CO₂ reduction. Typically, a series of samples (named Cu-1h, Cu-2h, Cu-3h and Cu-4h) were prepared via the redox reactions for various time from 1 to …

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 …

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 …