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Jun-Hua Jiang
Nuclear Science and Technology Directorate, Idaho National Laboratory, Idaho Falls, ID 83415, USA

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Journal article
Published: 26 March 2021 in Electrochem
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The electrodeposition of Al was investigated in an ionic liquid (IL), with 1-ethyl-3-methylimidazolium tetrachloroaluminate ([EMIm]AlCl4) as the electrolyte with AlCl3 precursor. The [EMIm]AlCl4 electrolyte exhibited a wide and stable electrochemical window from 3.2 to 2.3 V on a glassy carbon electrode when temperature was increased from 30 °C to 110 °C. The addition of AlCl3 into [EMIm]AlCl4 generated significant well-developed nucleation growth loops, and new coupled reduction and oxidation peaks in cyclic voltammograms corresponding to the Al deposition and dissolution, respectively. A calculation model was proposed predicting compositions of anions in AlCl3/[EMIm]AlCl4 system, and [Al2Cl7]− was found to be the active species for Al deposition. In AlCl3/[EMIm]AlCl4 (1:5), the reduction rate constants were 1.18 × 10−5 cm s−1 and 3.37 × 10−4 cm s−1 at 30 °C and 110 °C, respectively. Scanning electron microscope (SEM), energy dispersive spectroscope (EDS), and X-ray diffraction (XRD) microscope results showed that the metallic Al film had been successfully deposited on glassy carbon electrodes through constant-potential cathodic reductions. The [EMIm]AlCl4 was a promising electrolyte directly used for Al deposition.

ACS Style

Meng Shi; Junhua Jiang; Haiyan Zhao. Electrodeposition of Aluminum in the 1-Ethyl-3-Methylimidazolium Tetrachloroaluminate Ionic Liquid. Electrochem 2021, 2, 185 -196.

AMA Style

Meng Shi, Junhua Jiang, Haiyan Zhao. Electrodeposition of Aluminum in the 1-Ethyl-3-Methylimidazolium Tetrachloroaluminate Ionic Liquid. Electrochem. 2021; 2 (2):185-196.

Chicago/Turabian Style

Meng Shi; Junhua Jiang; Haiyan Zhao. 2021. "Electrodeposition of Aluminum in the 1-Ethyl-3-Methylimidazolium Tetrachloroaluminate Ionic Liquid." Electrochem 2, no. 2: 185-196.

Journal article
Published: 01 May 2020 in ECS Meeting Abstracts
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Nanostructuring surface layers of a metallic electrode is of particular interest for a wide range of potential applications because the nanostructures can not only increase the active area accessible to liquid or gaseous media and reactants but also improve electron mobility in the solid ligaments. In the past two decades, several strategies have been developed to design and fabricate nanostructured electrodes with highly ordered networks and high surface area [1]. Template synthesis is a popular approach for preparing nanoporous metals ranging from microporous to macroporous, and further to hierarchical porous structures. The control over the nanostructures enables systematically experimental and theoretical studies of the electrode structure-activity relationship. Despite the great success of the template syntheses, they are limited to producing nanoporous thin films or macroparticles with irregular morphologies. Since the shape and size distribution of nanostructures are critical parameters of their function and utility for specific applications, the preparation of porous metal nanostructures with a well-defined shape is highly desirable and technologically important. For this purpose, surfactant mediated synthesis has received considerable attention in the fabrication of nanoporous metal structures. A seeding reduction method has been developed to synthesize nanoporous platinum and other metals. The nanoporous structures exhibit remarkable surfactant-dependent morphological properties. The above techniques provide a formidable toolkit for nanostructuring electrode materials and have been dramatically utilized in the manufacturing of electrochemical systems. However, the high cost of the manufacturing of nanostructures is still a barrier to their commercial implementation into the advanced systems. The cost-reduction of the manufacturing techniques is one crucial target for continued research. For the above purposes, a unique electrochemical method based on one-pot electrochemical deposition and dissolution of metal atoms onto a target electrode substrate is a front-runner technology. Based on this method, metal atoms deposit from their corresponding metal ions and are directed to "attack" the substrate electrode in the electrodeposition mode, and they are removed from the substrate in the subsequent electro-dissolution mode. Moreover, the electrochemical deposition and dissolution of metal atoms can be conveniently manipulated through simple potential modulation such as potential cycles. In principle, no net consumption of chemicals such as metal salts, can be achieved. A range of metallic and alloy electrodes have been successfully nanostructured using different electrolytic metal atoms by this method [2, 3]. Some of them have demonstrated impressive performance for several different application in electrocatalysis, energy storage, and sensors. In this presentation, we will introduce the thermodynamic and kinetic fundamentals of this manufacturing technique, the characterization of resulting nanostructures, the analysis of their electrochemical behavior, the implementation of this technique for the development of advanced electrodes, and a preliminary economic analysis of this technique. References [1] J. Zhang and C. Li, Nanoporous metals: fabrication strategies and advanced electrochemical applications in catalysis, sensing and energy systems, Chem. Soc. Rev., 41, 7016 (2012). [2] Y. Yuan, W. Xiao, Z. Wang, D. Fray and X. Jin, Efficient nanostructurating of silicon by electrochemical alloying/dealloying in molten salts for improved lithium storage, Angew. Chem. Int. Ed., 57, 15743 (2018). [3] J. Jiang, Fabrication of uniform nanoparticulate gold through potential-modulated electrochemical deposition and dissolution of silver in ionic liquids, J. Electrochem. Soc., 166, E521 (2019).

ACS Style

Junhua Jiang; Congjian Wang. (Invited) Electrolytic Metal Atoms Enabled Manufacturing of Nanoporous Structures. ECS Meeting Abstracts 2020, MA2020-01, 2800 -2800.

AMA Style

Junhua Jiang, Congjian Wang. (Invited) Electrolytic Metal Atoms Enabled Manufacturing of Nanoporous Structures. ECS Meeting Abstracts. 2020; MA2020-01 (51):2800-2800.

Chicago/Turabian Style

Junhua Jiang; Congjian Wang. 2020. "(Invited) Electrolytic Metal Atoms Enabled Manufacturing of Nanoporous Structures." ECS Meeting Abstracts MA2020-01, no. 51: 2800-2800.

Journal article
Published: 01 May 2020 in ECS Meeting Abstracts
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ACS Style

Junhua Jiang; Congjian Wang. Electrochemical Detection Using Nanoporous Structures. ECS Meeting Abstracts 2020, MA2020-01, 2224 -2224.

AMA Style

Junhua Jiang, Congjian Wang. Electrochemical Detection Using Nanoporous Structures. ECS Meeting Abstracts. 2020; MA2020-01 (29):2224-2224.

Chicago/Turabian Style

Junhua Jiang; Congjian Wang. 2020. "Electrochemical Detection Using Nanoporous Structures." ECS Meeting Abstracts MA2020-01, no. 29: 2224-2224.

Review
Published: 24 January 2020 in Biofuels, Bioproducts and Biorefining
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Electrode and electrolyte materials with higher performance, longer life, and lower cost need to be developed, given the substantial growing demand for advanced electrochemical energy systems. Lignin, the second most abundant natural polymer, has been successfully demonstrated to be a viable precursor or feedstock for the preparation of high‐performance electrochemical energy materials and components such as electrodes, electrolyte additives, membrane separators, and binders. Moreover, techno‐economic analyses indicate that it is possible to prepare cost‐effective carbon structures from lignin at engineering scale, in contrast with current carbon products. These facts suggest that the scalable conversion of lignin into high‐value energy materials will offer a promising pathway to not only promote the utilization and valorization of lignin but also boost the development of advanced electrochemical energy systems. This review examines cutting‐edge renewable energy materials derived from various lignin compounds and their applications in electrochemical energy systems with an emphasis on supercapacitors, rechargeable batteries, and fuel cells. Meanwhile, this review also aims to carve out the critical barriers for lignin‐derived high‐performance materials for energy applications, and to identify viable approaches for the synthesis of sustainable new energy materials. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd

ACS Style

Xiaoyu Wu; Junhua Jiang; Chongmin Wang; Jian Liu; Yunqiao Pu; Arthur Ragauskas; Songmei Li; Bin Yang. Lignin‐derived electrochemical energy materials and systems. Biofuels, Bioproducts and Biorefining 2020, 14, 650 -672.

AMA Style

Xiaoyu Wu, Junhua Jiang, Chongmin Wang, Jian Liu, Yunqiao Pu, Arthur Ragauskas, Songmei Li, Bin Yang. Lignin‐derived electrochemical energy materials and systems. Biofuels, Bioproducts and Biorefining. 2020; 14 (3):650-672.

Chicago/Turabian Style

Xiaoyu Wu; Junhua Jiang; Chongmin Wang; Jian Liu; Yunqiao Pu; Arthur Ragauskas; Songmei Li; Bin Yang. 2020. "Lignin‐derived electrochemical energy materials and systems." Biofuels, Bioproducts and Biorefining 14, no. 3: 650-672.

Journal article
Published: 01 January 2020 in Journal of The Electrochemical Society
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Sensing materials play a key role in the successful implementation of electrochemical sensors, and nanotechnology has emerged as an important and rapidly growing field for stimulating the innovation of high-performance sensors. The fabrication, characterization, and evaluation of the nanostructured electrodes are therefore a focus of this field. Compared to a variety of dry and wet technologies which have been extensively developed for this purpose, electrochemical methods are typically convenient, highly effective, and potentially low-cost for the production of different nanostructures. This minireview is designed to introduce a unique electrochemical method - electrolytic metal-atom enabled manufacturing (EM2) and its application in electrochemical sensors. The EM2 technique employs electrolytic metal atoms generated from their corresponding salt precursor as a tool to nanostructure a wide range of substrate electrodes used in electrochemical sensors, based on a one-pot electrochemical deposition and dissolution of the metal atoms in the same electrolyte bath. Briefly, the metal atoms are electrodeposited on a substrate electrode during the cathode reduction, and they are selectively removed from the substrate during the subsequent anode oxidation. Because of the interactions between the electrolytic metal atoms and the substrate atoms, the repetitive electrodeposition and dissolution of the former on the substrate enable the nanostructuration of the substrate, particularly within its surface layers. The nanostructured electrodes have demonstrated very attractive performance for the determination of numerous analytes, such as high sensitivity and selectivity, high interference tolerance, and low detection limits. However, the EM2 technique and the application of the resulting nanostructured electrodes in electrochemical sensors and beyond have still been very limitedly investigated. In order to bring the community from academic, industries, agencies, and customers together to develop the EM2 technique and advance electrochemical sensor systems, this minireview will introduce the thermodynamic and kinetic fundamentals of this technique, the characterization of resulting nanostructures, the analysis of their electrochemical behavior, and the implementation of this technique for the development of advanced sensor electrodes. Finally, an outlook with a focus on further research areas is provided.

ACS Style

Junhua Jiang; Congjian Wang. Review—Electrolytic Metal Atoms Enabled Manufacturing of Nanostructured Sensor Electrodes. Journal of The Electrochemical Society 2020, 167, 037521 .

AMA Style

Junhua Jiang, Congjian Wang. Review—Electrolytic Metal Atoms Enabled Manufacturing of Nanostructured Sensor Electrodes. Journal of The Electrochemical Society. 2020; 167 (3):037521.

Chicago/Turabian Style

Junhua Jiang; Congjian Wang. 2020. "Review—Electrolytic Metal Atoms Enabled Manufacturing of Nanostructured Sensor Electrodes." Journal of The Electrochemical Society 167, no. 3: 037521.

Conference paper
Published: 01 January 2020 in Transactions of the American Nuclear Society - Volume 122
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ACS Style

Junhua Jiang; C. Wang. Room-Temperature Electrodeposition of Aluminum Coating from 1-Ethyl-3-Methylimidazolium Tetrachloroaluminate Based Ionic Liquid Bath. Transactions of the American Nuclear Society - Volume 122 2020, 122, 257 -258.

AMA Style

Junhua Jiang, C. Wang. Room-Temperature Electrodeposition of Aluminum Coating from 1-Ethyl-3-Methylimidazolium Tetrachloroaluminate Based Ionic Liquid Bath. Transactions of the American Nuclear Society - Volume 122. 2020; 122 (1):257-258.

Chicago/Turabian Style

Junhua Jiang; C. Wang. 2020. "Room-Temperature Electrodeposition of Aluminum Coating from 1-Ethyl-3-Methylimidazolium Tetrachloroaluminate Based Ionic Liquid Bath." Transactions of the American Nuclear Society - Volume 122 122, no. 1: 257-258.

Journal article
Published: 11 December 2019 in Journal of The Electrochemical Society
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A novel green-chemistry process for etching polycrystalline gold has been successfully developed by tuning electrochemical deposition and dissolution of metallic copper onto and away from gold in an ionic liquid bath based on a copper assisted etching mechanism. During the cathodic reduction of Cu from CuCl2 dissolved in the ionic liquid, the interaction of the electrodeposited Cu layer and the gold substrate leads to not only the formation of interfacial Cu-Au alloy intermediates but also the diffusion of Au into the Cu layer. During the subsequent anodic oxidation of Cu, the Au components in both the intermediates and the Cu layer are removed from the Au substrate, resulting in its etching. Cyclic voltammograms of CuCl2 on the Au electrode in 1-ethyl-3-methylimidazolium chloride in the potential range of approximately −1.50 to 0.60 V vs a silver pseudo reference electrode, exhibit the reduction and oxidation peaks associated with the redox couples of copper species. Scanning-electron-microscope studies of the samples treated in the CuCl2-containing ionic liquid by potential cycles clearly demonstrate the etching of the Au substrate. Elemental X-ray diffraction analyses of the etched Au substrate reveal that there is no detectable Cu residue in the etched substrate. Furthermore, our calculation suggests that the Cu assisting method can obtain an etching rate of approximately 105 nm/min, favorably comparable to those of several dry and wet etching methods.

ACS Style

Junhua Jiang. Copper-Assisted Etching of Gold through Electrochemical Deposition and Dissolution of Copper in Ionic Liquids. Journal of The Electrochemical Society 2019, 166, D940 -D945.

AMA Style

Junhua Jiang. Copper-Assisted Etching of Gold through Electrochemical Deposition and Dissolution of Copper in Ionic Liquids. Journal of The Electrochemical Society. 2019; 166 (16):D940-D945.

Chicago/Turabian Style

Junhua Jiang. 2019. "Copper-Assisted Etching of Gold through Electrochemical Deposition and Dissolution of Copper in Ionic Liquids." Journal of The Electrochemical Society 166, no. 16: D940-D945.

Journal article
Published: 06 November 2019 in Journal of The Electrochemical Society
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Nanoparticulate gold (NPG) has been successfully produced from polycrystalline Au by a novel method based on potential-modulated electrochemical deposition and dissolution of silver in an ionic liquid bath comprising of 1-ethyl-3-methylimidazolium chloride and silver nitrate at elevated temperatures. Cyclic voltammetric measurements exhibit that the potential cycles between −1.0 and 0.75 V versus a silver pseudo reference electrode can drive the electrochemical deposition and dissolution of silver onto and away from the Au electrode. Scanning electron microscope studies show that the NPG resulting from the potential cycles has very narrow particle size distribution with an average diameter of approximately 50 nm and is free of elemental Ag residue. As compared to a bulk Au electrode, the NPG electrode demonstrates substantially enhanced electrochemical responses. It exhibits a seven-time higher electro-catalytic activity toward the electrooxidation of nitrite in acidic media.

ACS Style

Junhua Jiang. Fabrication of Uniform Nanoparticulate Gold through Potential-Modulated Electrochemical Deposition and Dissolution of Silver in Ionic Liquids. Journal of The Electrochemical Society 2019, 166, E521 -E525.

AMA Style

Junhua Jiang. Fabrication of Uniform Nanoparticulate Gold through Potential-Modulated Electrochemical Deposition and Dissolution of Silver in Ionic Liquids. Journal of The Electrochemical Society. 2019; 166 (15):E521-E525.

Chicago/Turabian Style

Junhua Jiang. 2019. "Fabrication of Uniform Nanoparticulate Gold through Potential-Modulated Electrochemical Deposition and Dissolution of Silver in Ionic Liquids." Journal of The Electrochemical Society 166, no. 15: E521-E525.

Journal article
Published: 14 March 2019 in Current Nanomaterials
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ACS Style

Junhua Jiang. Free-Standing Mesoporous Biocarbon Papers Based High-Rate Supercapacitor. Current Nanomaterials 2019, 3, 178 -189.

AMA Style

Junhua Jiang. Free-Standing Mesoporous Biocarbon Papers Based High-Rate Supercapacitor. Current Nanomaterials. 2019; 3 (3):178-189.

Chicago/Turabian Style

Junhua Jiang. 2019. "Free-Standing Mesoporous Biocarbon Papers Based High-Rate Supercapacitor." Current Nanomaterials 3, no. 3: 178-189.

Journal article
Published: 01 January 2019 in ECS Meeting Abstracts
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Electrochemical surface treatment of metals offers a cost-effective and convenient approach to create highly-functional surfaces and produce nanostructured materials, for a wide range of potential applications such as electrochemical sensing, energy storage, and manufacturing. Different from ordinary electrochemical surface-treatment technologies, our work has investigated a green ionic-liquid based electrochemical process which can be tuned by introducing foreign metal ions into the ionic liquid for the purpose mentioned above. In the electrochemical process, the foreign metal ions deposit onto a bulk metal in an electrodeposition mode, and are regenerated in a subsequent electro-dissolution mode. Their in-situ electrochemical deposition-dissolution on the bulk metal can be tuned by controlling electrochemical driving forces such as currents or overpotentials and the composition of the ionic-liquid bath. The structures of the treated bulk metal may be strongly dependent upon the interactions between the bulk metal and the foreign metal electrodeposited, and their electrochemical activities in the ionic liquid. Figure 1 shows three distinct nanostructures of gold surfaces treated using three different foreign metal ions added to an ionic liquid bath, suggesting that it is possible to not only prepare highly actively gold electrodes for sensor and catalyst applications, but also produce nanostructured materials such as nanoporous and nanospherical gold powder. In this presentation, we will introduce our green-chemistry method tuned by the electrochemical deposition and dissolution of foreign metal ions in ionic liquids, as well as the characterization of resulting surface nanostructures and their applications to electrochemical sensing and energy storage. Figure 1

ACS Style

Junhua Jiang; Matthew Kerr. Foreign Metal-Ions Tuned Electrochemical Processes in Ionic Liquids for Bulk-Metal Surface Treatment. ECS Meeting Abstracts 2019, 1 .

AMA Style

Junhua Jiang, Matthew Kerr. Foreign Metal-Ions Tuned Electrochemical Processes in Ionic Liquids for Bulk-Metal Surface Treatment. ECS Meeting Abstracts. 2019; ():1.

Chicago/Turabian Style

Junhua Jiang; Matthew Kerr. 2019. "Foreign Metal-Ions Tuned Electrochemical Processes in Ionic Liquids for Bulk-Metal Surface Treatment." ECS Meeting Abstracts , no. : 1.

Journal article
Published: 01 January 2019 in ECS Meeting Abstracts
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Incorporation of highly active nanostructures into metallic electrode surface layers is of particular interest for a wide range of potential applications, such as electrochemical sensing and energy storage-conversion systems, because the nanostructures not only can increase the active area accessible to reactant molecules but can also improve electron mobility in the solid ligaments. However, controlling the nano-architecture of electrode surface layers faces great challenges since metals at nanoscale favor low surface areas in order to minimize the surface energy. In the past two decades, several strategies such as template synthesis, surfactant mediated synthesis and dealloying, have been developed to design and fabricate nanostructured electrodes with highly ordered networks and high surface area. We have developed a green-chemistry method based on in-situ electrochemical deposition-dissolution (ECDD) of an active metal on a target metal substrate in ionic liquids to achieve the nanostructuration of metallic electrodes.1-4 As shown in Figure 1A, during electrochemical deposition, a highly reactive metal component such as Zn is introduced via electrodeposition to interact with a less active electrode substrate such as Au to form an alloy phase. During subsequent electrochemical dissolution, the reactive component is selectively removed from the alloy phase leading to the formation of nanostructured surface layers. The nanostructured layers can grow deeper by repeating the process. The most obvious advantage of the ECDD method over other arts is that no net chemicals are consumed and it is a green-chemistry process. This method has been employed to successfully create different nanostructures on single-element metal and alloy electrodes at tens-to-hundreds micrometer scales, which are shown in Figure 1B to E. In this presentation, we will introduce the green-chemistry method based on the electrochemical alloying-dealloying in ionic liquids, the characterization and polarization behavior of resulting surface nanostructures, further catalysis of the nanostructures, and their applications to electrochemical sensing and energy storage conversion. References [1] J. Jiang, N. Holm, K. O'Brien, ECS Journal of Solid State Science and Technology 4 (2015) S3024-S3029. [2] J. Jiang, L. Zhang, Electroanalysis 29 (2017) 2019-2026. [3] J. Jiang, L. Zhang, ECS Journal of Solid State Science and Technology 4 (2015) N5084-N5088. [4] J. Jiang, L. Zhang, X. Wang, ACS Appl. Mater. Interfaces 5 (2013) 12689–12694. Figure 1

ACS Style

Junhua Jiang; Robert Mariani. Microscale Surface Nanostructuration and Catalysis of Metallic Electrodes through Electrochemical Deposition and Dissolution in Ionic Liquids. ECS Meeting Abstracts 2019, 1 .

AMA Style

Junhua Jiang, Robert Mariani. Microscale Surface Nanostructuration and Catalysis of Metallic Electrodes through Electrochemical Deposition and Dissolution in Ionic Liquids. ECS Meeting Abstracts. 2019; ():1.

Chicago/Turabian Style

Junhua Jiang; Robert Mariani. 2019. "Microscale Surface Nanostructuration and Catalysis of Metallic Electrodes through Electrochemical Deposition and Dissolution in Ionic Liquids." ECS Meeting Abstracts , no. : 1.

Full paper
Published: 19 June 2017 in Electroanalysis
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Nanostructured platinum‐iridium alloy microelectrode with high surface area was successfully prepared by applying successive potential cycles to a conventional PtIr microdisc in ionic liquid electrolyte containing ZnCl2 at elevated temperature. Scanning‐electron microscope studies show that a very thin nanostructured film was created on the electrode upon 20 potential cycles between −2.0 and 0.75 V versus a Ag pseudo‐reference electrode. The film nanostructures are characteristic of regular hill‐like nano‐spacings separated by valley‐like nano‐cracks, and a roughness factor of approximately 40. The nanostructured electrode is highly active towards electrochemical oxidation of ammonia, and generates a linear relation between voltammetric peak currents (or chronoamperometric currents), and logarithm of ammonia concentration in a range of approximately 1 ppm to 10000 ppm. It has been proposed that the Temkin adsorption of ammonia from the bulk solution onto the electrode surfaces was involved in its electrochemical oxidation and could be responsible for the linear current‐logarithmic concentration relation.

ACS Style

Junhua Jiang; Lei Zhang. Nanostructured Platinum-iridium Alloy Microelectrode for Ammonia Determination. Electroanalysis 2017, 29, 2019 -2026.

AMA Style

Junhua Jiang, Lei Zhang. Nanostructured Platinum-iridium Alloy Microelectrode for Ammonia Determination. Electroanalysis. 2017; 29 (9):2019-2026.

Chicago/Turabian Style

Junhua Jiang; Lei Zhang. 2017. "Nanostructured Platinum-iridium Alloy Microelectrode for Ammonia Determination." Electroanalysis 29, no. 9: 2019-2026.

Journal article
Published: 03 May 2017 in Journal of The Electrochemical Society
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A supercapacitor comprising of two binder-free biochar monolith electrodes and 1-butyl-3-methylimidazolium tetrafluoroborate based ionic liquid electrolyte was studied at room temperature and 140°C by cyclic voltammetry, constant-current charge-discharge, and electrochemical impedance spectroscopy. The supercapacitor exhibits an operating voltage window of approximately 6 V. It is found that increasing temperature from room temperature to 140°C considerably increases its specific mass capacity and its charge-discharge rate by a factor of approximately 10. The specific capacity of the supercapacitor calculated from the voltammetric measurements depended on scan rates. At 140°C, a capacity of 21 F g−1 was obtained at 5 mV s−1 and this value decreases to around 10 F g−1 at 100 mV s−1; the constant-current charge-discharge profiles exhibit pseudo-linear voltage-time responses during the discharges. The supercapacitor shows good stability characteristics of no obvious performance decay after 1000 cycles within a voltage window of 6 V. Electrochemical impedance spectra of the supercapacitor display a wide linear region corresponding to diffusion control. The energy densities of the supercapacitor that are normalized to the total active electrode materials are higher than 20 Wh kg−1 when its power density is lower than 2000 W kg−1. These facts suggest that the high-temperature biochar supercapacitor would be a promising energy-storage device with high energy and power density.

ACS Style

Junhua Jiang. High Temperature Monolithic Biochar Supercapacitor Using Ionic Liquid Electrolyte. Journal of The Electrochemical Society 2017, 164, H5043 -H5048.

AMA Style

Junhua Jiang. High Temperature Monolithic Biochar Supercapacitor Using Ionic Liquid Electrolyte. Journal of The Electrochemical Society. 2017; 164 (8):H5043-H5048.

Chicago/Turabian Style

Junhua Jiang. 2017. "High Temperature Monolithic Biochar Supercapacitor Using Ionic Liquid Electrolyte." Journal of The Electrochemical Society 164, no. 8: H5043-H5048.

Journal article
Published: 01 February 2017 in Electrochemistry Communications
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ACS Style

Junhua Jiang. Promotion of PtIr and Pt catalytic activity towards ammonia electrooxidation through the modification of Zn. Electrochemistry Communications 2017, 75, 52 -55.

AMA Style

Junhua Jiang. Promotion of PtIr and Pt catalytic activity towards ammonia electrooxidation through the modification of Zn. Electrochemistry Communications. 2017; 75 ():52-55.

Chicago/Turabian Style

Junhua Jiang. 2017. "Promotion of PtIr and Pt catalytic activity towards ammonia electrooxidation through the modification of Zn." Electrochemistry Communications 75, no. : 52-55.

Journal article
Published: 04 August 2015 in ECS Journal of Solid State Science and Technology
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A nanoporous gold (NPG) microelectrode with high catalytic activity was prepared by applying potential cycles to a polycrystalline Au-disk microelectrode in an ionic liquid electrolyte containing ZnCl2 at elevated temperature. Scanning-electron microscope measurements showed that the nanoporous structures of the NPG microelectrode are characteristic of nanopores and ligament spacings. The response of the NPG microelectrode to both As(III) and As(V) was studied in dilute HNO3 media using cyclic voltammetry and anodic stripping voltammetry, and compared to those of the Au-disk microelectrode. It was found that both the amounts of As per unit surface area deposited through the reduction of As(III) as well as the Faradaic reversibility associated with the As deposition and its corresponding anodic dissolution were significantly higher on the NPG than on the Au-disk. They contribute to higher anodic stripping peaks observed on the NPG. A limit of detection of 20 nM and, more importantly, a 10-fold enhancement of sensitivity were obtained on the NPG microelectrode. These values suggest that the NPG microelectrode may lead to an efficient and low-cost technique for electrochemical detection of As(III) in water. However, both the NPG and Au-disk microelectrodes showed no response to As(V) under similar conditions.

ACS Style

Junhua Jiang; Nancy Holm; Kevin O'brien. Improved Anodic Stripping Voltammetric Detection of Arsenic (III) Using Nanoporous Gold Microelectrode. ECS Journal of Solid State Science and Technology 2015, 4, S3024 -S3029.

AMA Style

Junhua Jiang, Nancy Holm, Kevin O'brien. Improved Anodic Stripping Voltammetric Detection of Arsenic (III) Using Nanoporous Gold Microelectrode. ECS Journal of Solid State Science and Technology. 2015; 4 (10):S3024-S3029.

Chicago/Turabian Style

Junhua Jiang; Nancy Holm; Kevin O'brien. 2015. "Improved Anodic Stripping Voltammetric Detection of Arsenic (III) Using Nanoporous Gold Microelectrode." ECS Journal of Solid State Science and Technology 4, no. 10: S3024-S3029.

Journal article
Published: 08 April 2015 in ECS Journal of Solid State Science and Technology
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ACS Style

Junhua Jiang; Lei Zhang. Creation of Nanoporous Ag Surface Layers through a Two-Stage Electrochemical Deposition-Dissolution of Zn and Intercalation-Deintercalation of Chloride Ions in an Ionic Liquid Bath. ECS Journal of Solid State Science and Technology 2015, 4, N5084 -N5088.

AMA Style

Junhua Jiang, Lei Zhang. Creation of Nanoporous Ag Surface Layers through a Two-Stage Electrochemical Deposition-Dissolution of Zn and Intercalation-Deintercalation of Chloride Ions in an Ionic Liquid Bath. ECS Journal of Solid State Science and Technology. 2015; 4 (6):N5084-N5088.

Chicago/Turabian Style

Junhua Jiang; Lei Zhang. 2015. "Creation of Nanoporous Ag Surface Layers through a Two-Stage Electrochemical Deposition-Dissolution of Zn and Intercalation-Deintercalation of Chloride Ions in an Ionic Liquid Bath." ECS Journal of Solid State Science and Technology 4, no. 6: N5084-N5088.

Journals
Published: 15 December 2014 in Journal of Materials Chemistry A
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High performance biochar carbon nanosheets for supercapacitors are synthesized from corn cob waste via a novel exfoliation approach.

ACS Style

Matthew Genovese; Junhua Jiang; Keryn Lian; Nancy Holm. High capacitive performance of exfoliated biochar nanosheets from biomass waste corn cob. Journal of Materials Chemistry A 2014, 3, 2903 -2913.

AMA Style

Matthew Genovese, Junhua Jiang, Keryn Lian, Nancy Holm. High capacitive performance of exfoliated biochar nanosheets from biomass waste corn cob. Journal of Materials Chemistry A. 2014; 3 (6):2903-2913.

Chicago/Turabian Style

Matthew Genovese; Junhua Jiang; Keryn Lian; Nancy Holm. 2014. "High capacitive performance of exfoliated biochar nanosheets from biomass waste corn cob." Journal of Materials Chemistry A 3, no. 6: 2903-2913.

Journal article
Published: 17 August 2014 in Journal of Applied Electrochemistry
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Biochar prepared from the pyrolysis of maple wood was studied as supercapacitor electrode materials. Three kinds of electrodes were fabricated: mini-chunk electrodes, thin-film electrodes, and large-disk-chunk electrodes. Their capacitive behaviors were studied using cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The mini-chunk supercapacitor shows an electrochemical behavior similar to the supercapacitor using the thin-film electrodes. It exhibits outstanding performance characteristic of a high specific capacitance of approximately 32 F g−1 and a high stability without obvious capacitance decays upon 2,600 potential cycles. This indicates that the mini-chunk supercapacitor can be used as an mF-scale power source for electronic device applications. Moreover, the mini-chunk electrode provides a simple and fast technique to evaluate biochar materials used as potentially high-performance, low-cost, and environmental friendly supercapacitor electrodes without the need of binder and complicated fabrication procedures. However, the supercapacitor using large-disk-chunk biochar electrodes shows lower specific capacitive performance due to the high ohmic resistance stemming from long tubular structures within biochar.

ACS Style

Lei Zhang; Junhua Jiang; Nancy Holm; Fangling Chen. Mini-chunk biochar supercapacitors. Journal of Applied Electrochemistry 2014, 44, 1145 -1151.

AMA Style

Lei Zhang, Junhua Jiang, Nancy Holm, Fangling Chen. Mini-chunk biochar supercapacitors. Journal of Applied Electrochemistry. 2014; 44 (10):1145-1151.

Chicago/Turabian Style

Lei Zhang; Junhua Jiang; Nancy Holm; Fangling Chen. 2014. "Mini-chunk biochar supercapacitors." Journal of Applied Electrochemistry 44, no. 10: 1145-1151.

Journal article
Published: 01 January 2014 in ECS Meeting Abstracts
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Direct alcohol fuel cells (DAFCs) possess obvious advantages over traditional hydrogen fuel cells in terms of hydrogen storage, transportation, and the utilization of existing infrastructure. However, the commercialization of this fuel cell technology based on the use of proton-conductive polymer membranes has been largely hindered by its low power density owing to the sluggish kinetics of both anode and cathode reactions in acidic media and high cost owing to the use of noble metal catalysts. These could be potentially addressed by the development of alkaline alcohol fuel cells (AAFCs). In alkaline media, the polarization characteristics of alcohol electrooxidation and oxygen electroreduction are far superior to those in acidic media. Another obvious advantage of using alkaline media is less-limitations of electrode materials. The replacement of Pt catalysts with non-Pt catalysts will significantly decrease the cost of catalysts. Recently, the AAFCs have received increased attention. However, these fuel cells are normally operated at temperature lower than 80 °C. In this low temperature range, both methanol electrooxidation and oxygen electroreduction reactions are not sufficiently facile for the development of high performance AAFCs. Considerable undergoing efforts are now focused on the development of highly active catalysts for accelerated electrode reactions. Alternatively, increasing temperature has been proven as an effective way to accelerate electrode reactions. The changes of the reaction rates with increasing temperature are strongly determined by the values of activation energy, as described by the Arrhenius equation. More obvious changes are expected for alcohol electrooxidation in alkaline media than in acidic media since reported values of the activation energy are higher in alkaline media. Additionally, increasing temperature may decrease concentration polarization, Ohmic polarization, and CO poisoning of the catalysts. All these advantages can contribute to the performance improvement of the AAFCs. In an intermediate temperature range of 80 to 200 oC, CO is likely to spontaneously react with OH- to give formate as follows [1]: (1) Because formate produced via Reaction I is soluble and more electrochemically active than CO on Pt, surface CO formed during alcohol oxidation would be readily removed, resulting in considerable decrease in the CO-poisoning of Pt-based catalysts. Moreover, the kinetics of the alcohol oxidation in alkaline media on Pt has been suggested to be largely determined by the reaction between the surface CO and surface oxygen-containing species (OH), following a Langmuir-Hinshinwood mechanism. Accordingly, accelerated electrooxidation of CO intermediate would increase the rate of the alcohol oxidation. Further finding of increasing temperature for the methanol oxidation is that methanol can be efficiently converted with water in the aqueous phase over appropriate heterogeneous catalysts at temperatures near 200 oC to produce primarily H2 and CO2 [2]. (2) During the methanol liquid-phase reforming, trace amount of methane is the side product and the use of more basic catalyst favors H2 production. The methanol reforming indicates that sluggish methanol oxidation reaction which has plagued low temperature DAFCs, could become highly facile in alkaline media at temperatures close to 200 oC where the reforming of methanol is triggered. Substantially accelerated electrooxidation of methanol would make it possible to achieve low anode overpotentials. Therefore, driving the electrooxidation of methanol in an intermediate-temperature range over the methanol-boiling temperature (around 80 oC) and the triggering temperature of the methanol reforming (about 200 oC) would be of academic and practical importance for the development of high performance a technology. We have investigated systematically the electrocatalysis associated with the ITAAFC and demonstrated high performance of this promising fuel cell technology. Our status-of-the-art ITAAFC operating with methanol at 120 oC demonstrated a peak power density of around 250 mW cm-2 at around 700 mA cm-2. References 1. J. van Trump, S. Miller, Earth Planet. Sci. Lett. 20, 145 (1973). 2. R. Davda, W. Shabaker, W. Huber, D. Cortright, and A. Dumesic, Applied Catalysis B: Environmental 56, 171 (2005).

ACS Style

Junhua Jiang. Operating Alkaline Alcohol Fuel Cell (ITAAFC) in Intermediate-Temperature Range. ECS Meeting Abstracts 2014, 1 .

AMA Style

Junhua Jiang. Operating Alkaline Alcohol Fuel Cell (ITAAFC) in Intermediate-Temperature Range. ECS Meeting Abstracts. 2014; ():1.

Chicago/Turabian Style

Junhua Jiang. 2014. "Operating Alkaline Alcohol Fuel Cell (ITAAFC) in Intermediate-Temperature Range." ECS Meeting Abstracts , no. : 1.

Journal article
Published: 01 December 2013 in Electrochimica Acta
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ACS Style

Junhua Jiang; Lei Zhang; Xinying Wang; Nancy Holm; Kishore Rajagopalan; Fanglin Chen; Shuguo Ma. Highly ordered macroporous woody biochar with ultra-high carbon content as supercapacitor electrodes. Electrochimica Acta 2013, 113, 481 -489.

AMA Style

Junhua Jiang, Lei Zhang, Xinying Wang, Nancy Holm, Kishore Rajagopalan, Fanglin Chen, Shuguo Ma. Highly ordered macroporous woody biochar with ultra-high carbon content as supercapacitor electrodes. Electrochimica Acta. 2013; 113 ():481-489.

Chicago/Turabian Style

Junhua Jiang; Lei Zhang; Xinying Wang; Nancy Holm; Kishore Rajagopalan; Fanglin Chen; Shuguo Ma. 2013. "Highly ordered macroporous woody biochar with ultra-high carbon content as supercapacitor electrodes." Electrochimica Acta 113, no. : 481-489.