Chung-Jui Su - Academia.edu (original) (raw)

Papers by Chung-Jui Su

ECS Meeting Abstracts, 2014

not Available.

ECS Meeting Abstracts, 2012

not Available.

ECS Meeting Abstracts, 2012

ECS Meeting Abstracts, 2012

ECS Electrochemistry Letters, 2015

Potential oscillation was observed during the template-free galvanostatic deposition in the 58/42... more Potential oscillation was observed during the template-free galvanostatic deposition in the 58/42 mol% AlCl 3 /trimethylamine hydrochloride ionic liquid, and resulted in the formation of unique periodic (accordion-like) aluminum wires with variable periodicity and diameter controlled by the deposition current density. Factors leading to this phenomenon are postulated.

Journal of the Electrochemical Society, 2015

Ionic liquid zinc chloride-1-ethyl-3-methylimidazolium chloride (IL ZnCl 2-EMICl) with a ZnCl 2 /... more Ionic liquid zinc chloride-1-ethyl-3-methylimidazolium chloride (IL ZnCl 2-EMICl) with a ZnCl 2 /EMICl ratio of 40/60 mol% was used as the electrolyte to study the voltammetric behavior of Se(IV) introduced into the IL as selenium chloride (SeCl 4) or selenium oxide (SeO 2). The electrodeposition of ZnSe was performed using constant-potential electrolysis at tungsten electrodes via a two-stage approach from the IL with and without SeO 2. The nucleation mechanism of Se at the tungsten electrodes agrees better with the three-dimensional instantaneous nucleation than the progressive nucleation based on Sharifker's model. Crystalline Se and approximately stoichiometric crystalline ZnSe electrodeposits could be obtained from this system. The ZnSe films showed photoelectrochemical activity with a bandgap energy of ∼2.5 eV. According to the experiments of the dependence of the photocurrent on the applied potential, the ZnSe film was determined to be a p-type semiconductor with the flatband potential V FB of −0.024 V (vs. Fc/Fc +).

The Journal of Physical Chemistry C, 2014

The growth of hollow tubes, nanowire array, and segmented porous nanowire arrays made of Cu−Zn al... more The growth of hollow tubes, nanowire array, and segmented porous nanowire arrays made of Cu−Zn alloys in a Lewis acidic ZnCl 2-1-ethyl-3-methylimidazolium chloride ionic liquid via direct electrodeposition without the need for a template is presented. The formation of each of type of structure is described. Hollow tubes result from the uneven overpotential gradient created at low Cu(I) concentration and low applied deposition overpotential. Nanowire arrays form under mass-transport-limited conditions, in which the ionic liquid speciation plays an important role. Segmented porous nanowire arrays are obtained by increasing the Cu(I) concentration to enhance the concentration profile vibration near the growth surface. The electrodeposited nanowire arrays show very good efficiency for the electrocatalytic reduction of nitrate ions in alkaline aqueous solution.

ECS Transactions, 2007

Two room temperature ionic liquids based on the bis ((trifluoromethyl)sulfonyl)-imide anion (TFSI... more Two room temperature ionic liquids based on the bis ((trifluoromethyl)sulfonyl)-imide anion (TFSI anion), the tributylmethylammonium-TFSI (Bu3MeN-TFSI) and the butylmethylpyrrolidinium-TFSI (BuMePy-TFSI), have been prepared for the electrochemical study of Li+/Li redox couple, the electrodeposition of Mn, Zn-Mn alloys and Cu-Mn alloys, and the extraction of Cu(II) ions from aqueous solutions, respectively. The best coulombic efficiency of Li+/Li couple is 97%. Mn(II), Zn(II) and Cu(I) species were introduced into the Bu3MeN-TFSI or BuMePy-TFSI by the anodic dissolution of the respective metallic electrodes. Coatings containing Mn, Zn, Cu, Zn-Mn or Cu-Mn can be obtained by controlled-potential electrolysis. The current efficiencies of Mn electrodeposition in either ionic liquid approach 100%. The Zn-Mn and Cu-Mn alloy deposits obtained in this study were compact and adherent. The surface morphology of these deposits depended on the Mn/Zn and Mn/Cu ratio, respectively. The BuMePy-TFSI...

Journal of Materials Chemistry, 2012

ABSTRACT Butylmethylpyrrolidinium–dicyanamide (BMP–DCA) ionic liquid (IL), which enables the pseu... more ABSTRACT Butylmethylpyrrolidinium–dicyanamide (BMP–DCA) ionic liquid (IL), which enables the pseudocapacitive behavior of a MnO2 electrode, performing over a wide potential range of 3 V, is considered to be a promising electrolyte for supercapacitors. Various additives are doped in this IL electrolyte in attempt to further improve the electrochemical performance of MnO2; NaDCA is found to be the most effective. An appropriate concentration (0.01 M) of NaDCA in the IL can optimize the capacitance of the MnO2 electrode; the values are 100 and 125 F g−1 at 25 and 50 °C, respectively. The NaDCA-doped IL is superior to traditional aqueous electrolytes for high-energy, high-power, elevated-temperature, and long-life MnO2 supercapacitor applications.

Journal of Electroanalytical Chemistry, 2010

The voltammetric behavior of Pt(II), Fe(II), and mixtures of Pt(II) and Fe(II) was studied in N-b... more The voltammetric behavior of Pt(II), Fe(II), and mixtures of Pt(II) and Fe(II) was studied in N-butyl-N-methylpyrrolidinium dicyanamide ionic liquid (BMP-DCA IL), N-butyl-N-methylpyrrolidinium bis((trifluoromethyl)sulfonyl)imide ionic liquid (BMP-TFSI IL), and a mixture of BMP-DCA and BMP-TFSI, respectively. Electrodeposition of PtFe coatings was achieved by controlled-potential electrolysis on tungsten from the aforementioned ILs containing Pt(II) and Fe(II). The Pt(II) species required to prepare these PtFe coatings was introduced into the ILs by addition of PtCl 2. In BMP-TFSI, an additional two equivalents of N-butyl-N-methylpyrrolidinium chloride (BMP-Cl) were essential to assist one equivalent of PtCl 2 to dissolve. The Fe(II) species was introduced into the ILs by addition of FeCl 2 or by anodizing an iron spiral electrode. In BMP-TFSI, additional BMP-Cl had to be added to assist FeCl 2 dissolution (FeCl 2 :BMP-Cl = 1:2 (mol:mol)). The PtFe coatings with various atomic ratios of Pt/Fe were studied for their voltammetric behavior towards the oxygen reduction reaction (ORR) in acidic solutions. This study shows that the PtFe alloy coatings with atomic ratios of $0.5/0.5 had the highest reductive current density for ORR, better than regular Pt or Pt-electrodeposited electrodes.

Electrochimica Acta, 2009

Extraction of Cu(II) from neutral aqueous solutions with the hydrophobic room-temperature ionic l... more Extraction of Cu(II) from neutral aqueous solutions with the hydrophobic room-temperature ionic liquid (IL) N-butyl-N-methylpyrrolidinium bis((trifluoromethyl)sulfonyl)imide (BMP-TFSI) in the presence of the pyridine-based ionophore N1,N1,N4,N4-tetrakis(2-(pyridin-2-yl)ethyl)butane-1,4-diamine (C4N2Py4) is demonstrated in this study. Although the distribution coefficients, DM, of Cu(II) extraction depend on the concentration of Cu(II) in aqueous solutions, all values were higher than 200, indicating extremely high extraction efficiency. Based

Corrosion Science, 2011

... To investigate the material corrosion characteristics, the surface morphologies and chemical ... more ... To investigate the material corrosion characteristics, the surface morphologies and chemical compositions of these samples were examined using a scanning electron microscope (SEM,Philip XL-40 FEG) and its auxiliary energy-dispersive X ... [3] P. Wasserscheid, T. Welton, Ionic ...

Chemistry - An Asian Journal, 2012

The hydrophobic ionic liquid N-butyl-N-methylpyrrolidinium bis((trifluoromethyl)sulfonyl)amide (B... more The hydrophobic ionic liquid N-butyl-N-methylpyrrolidinium bis((trifluoromethyl)sulfonyl)amide (BMP-TFSA IL), which contains a series of flexible ionophores of polypyridine-type small molecules or two rigid ionophores of peripherally pyridine-modified PAMAM dendrimers, was used to extract cupric ions from aqueous solutions. The polypyridine-type ionophores show good selectivity toward cupric ions at pH 2. The selectivity is affected by the spacing between the two amino groups. However, the pyridine-modified dendrimers showed poor selectivity, although their extraction efficiency still depended on the pH of the aqueous solution. The ionic liquids that contained small molecular ionophores and their dendrimer analogs were reused after acid washing or electrochemical reduction. During acid washing, the nitrogen atoms of the ionophores were protonated to release the cupric ions into the aqueous phase, and the copper atoms were deposited onto the electrode surface during the electrochemical reduction accompanied by the regeneration of the ionophores.

Electrochemistry Communications, 2013

RSC Advances, 2016

Beaded aluminum wires with tunable physical morphology were prepared from a chloroaluminate ionic... more Beaded aluminum wires with tunable physical morphology were prepared from a chloroaluminate ionic liquid using a template-free square-wave pulse potential electrodeposition method with various pulse potential and duration combinations.

ECS Meeting Abstracts, 2014

not Available.

ECS Meeting Abstracts, 2012

not Available.

ECS Meeting Abstracts, 2012

ECS Meeting Abstracts, 2012

ECS Electrochemistry Letters, 2015

Potential oscillation was observed during the template-free galvanostatic deposition in the 58/42... more Potential oscillation was observed during the template-free galvanostatic deposition in the 58/42 mol% AlCl 3 /trimethylamine hydrochloride ionic liquid, and resulted in the formation of unique periodic (accordion-like) aluminum wires with variable periodicity and diameter controlled by the deposition current density. Factors leading to this phenomenon are postulated.

Journal of the Electrochemical Society, 2015

Ionic liquid zinc chloride-1-ethyl-3-methylimidazolium chloride (IL ZnCl 2-EMICl) with a ZnCl 2 /... more Ionic liquid zinc chloride-1-ethyl-3-methylimidazolium chloride (IL ZnCl 2-EMICl) with a ZnCl 2 /EMICl ratio of 40/60 mol% was used as the electrolyte to study the voltammetric behavior of Se(IV) introduced into the IL as selenium chloride (SeCl 4) or selenium oxide (SeO 2). The electrodeposition of ZnSe was performed using constant-potential electrolysis at tungsten electrodes via a two-stage approach from the IL with and without SeO 2. The nucleation mechanism of Se at the tungsten electrodes agrees better with the three-dimensional instantaneous nucleation than the progressive nucleation based on Sharifker's model. Crystalline Se and approximately stoichiometric crystalline ZnSe electrodeposits could be obtained from this system. The ZnSe films showed photoelectrochemical activity with a bandgap energy of ∼2.5 eV. According to the experiments of the dependence of the photocurrent on the applied potential, the ZnSe film was determined to be a p-type semiconductor with the flatband potential V FB of −0.024 V (vs. Fc/Fc +).

The Journal of Physical Chemistry C, 2014

The growth of hollow tubes, nanowire array, and segmented porous nanowire arrays made of Cu−Zn al... more The growth of hollow tubes, nanowire array, and segmented porous nanowire arrays made of Cu−Zn alloys in a Lewis acidic ZnCl 2-1-ethyl-3-methylimidazolium chloride ionic liquid via direct electrodeposition without the need for a template is presented. The formation of each of type of structure is described. Hollow tubes result from the uneven overpotential gradient created at low Cu(I) concentration and low applied deposition overpotential. Nanowire arrays form under mass-transport-limited conditions, in which the ionic liquid speciation plays an important role. Segmented porous nanowire arrays are obtained by increasing the Cu(I) concentration to enhance the concentration profile vibration near the growth surface. The electrodeposited nanowire arrays show very good efficiency for the electrocatalytic reduction of nitrate ions in alkaline aqueous solution.

ECS Transactions, 2007

Two room temperature ionic liquids based on the bis ((trifluoromethyl)sulfonyl)-imide anion (TFSI... more Two room temperature ionic liquids based on the bis ((trifluoromethyl)sulfonyl)-imide anion (TFSI anion), the tributylmethylammonium-TFSI (Bu3MeN-TFSI) and the butylmethylpyrrolidinium-TFSI (BuMePy-TFSI), have been prepared for the electrochemical study of Li+/Li redox couple, the electrodeposition of Mn, Zn-Mn alloys and Cu-Mn alloys, and the extraction of Cu(II) ions from aqueous solutions, respectively. The best coulombic efficiency of Li+/Li couple is 97%. Mn(II), Zn(II) and Cu(I) species were introduced into the Bu3MeN-TFSI or BuMePy-TFSI by the anodic dissolution of the respective metallic electrodes. Coatings containing Mn, Zn, Cu, Zn-Mn or Cu-Mn can be obtained by controlled-potential electrolysis. The current efficiencies of Mn electrodeposition in either ionic liquid approach 100%. The Zn-Mn and Cu-Mn alloy deposits obtained in this study were compact and adherent. The surface morphology of these deposits depended on the Mn/Zn and Mn/Cu ratio, respectively. The BuMePy-TFSI...

Journal of Materials Chemistry, 2012

ABSTRACT Butylmethylpyrrolidinium–dicyanamide (BMP–DCA) ionic liquid (IL), which enables the pseu... more ABSTRACT Butylmethylpyrrolidinium–dicyanamide (BMP–DCA) ionic liquid (IL), which enables the pseudocapacitive behavior of a MnO2 electrode, performing over a wide potential range of 3 V, is considered to be a promising electrolyte for supercapacitors. Various additives are doped in this IL electrolyte in attempt to further improve the electrochemical performance of MnO2; NaDCA is found to be the most effective. An appropriate concentration (0.01 M) of NaDCA in the IL can optimize the capacitance of the MnO2 electrode; the values are 100 and 125 F g−1 at 25 and 50 °C, respectively. The NaDCA-doped IL is superior to traditional aqueous electrolytes for high-energy, high-power, elevated-temperature, and long-life MnO2 supercapacitor applications.

Journal of Electroanalytical Chemistry, 2010

The voltammetric behavior of Pt(II), Fe(II), and mixtures of Pt(II) and Fe(II) was studied in N-b... more The voltammetric behavior of Pt(II), Fe(II), and mixtures of Pt(II) and Fe(II) was studied in N-butyl-N-methylpyrrolidinium dicyanamide ionic liquid (BMP-DCA IL), N-butyl-N-methylpyrrolidinium bis((trifluoromethyl)sulfonyl)imide ionic liquid (BMP-TFSI IL), and a mixture of BMP-DCA and BMP-TFSI, respectively. Electrodeposition of PtFe coatings was achieved by controlled-potential electrolysis on tungsten from the aforementioned ILs containing Pt(II) and Fe(II). The Pt(II) species required to prepare these PtFe coatings was introduced into the ILs by addition of PtCl 2. In BMP-TFSI, an additional two equivalents of N-butyl-N-methylpyrrolidinium chloride (BMP-Cl) were essential to assist one equivalent of PtCl 2 to dissolve. The Fe(II) species was introduced into the ILs by addition of FeCl 2 or by anodizing an iron spiral electrode. In BMP-TFSI, additional BMP-Cl had to be added to assist FeCl 2 dissolution (FeCl 2 :BMP-Cl = 1:2 (mol:mol)). The PtFe coatings with various atomic ratios of Pt/Fe were studied for their voltammetric behavior towards the oxygen reduction reaction (ORR) in acidic solutions. This study shows that the PtFe alloy coatings with atomic ratios of $0.5/0.5 had the highest reductive current density for ORR, better than regular Pt or Pt-electrodeposited electrodes.

Electrochimica Acta, 2009

Extraction of Cu(II) from neutral aqueous solutions with the hydrophobic room-temperature ionic l... more Extraction of Cu(II) from neutral aqueous solutions with the hydrophobic room-temperature ionic liquid (IL) N-butyl-N-methylpyrrolidinium bis((trifluoromethyl)sulfonyl)imide (BMP-TFSI) in the presence of the pyridine-based ionophore N1,N1,N4,N4-tetrakis(2-(pyridin-2-yl)ethyl)butane-1,4-diamine (C4N2Py4) is demonstrated in this study. Although the distribution coefficients, DM, of Cu(II) extraction depend on the concentration of Cu(II) in aqueous solutions, all values were higher than 200, indicating extremely high extraction efficiency. Based

Corrosion Science, 2011

... To investigate the material corrosion characteristics, the surface morphologies and chemical ... more ... To investigate the material corrosion characteristics, the surface morphologies and chemical compositions of these samples were examined using a scanning electron microscope (SEM,Philip XL-40 FEG) and its auxiliary energy-dispersive X ... [3] P. Wasserscheid, T. Welton, Ionic ...

Chemistry - An Asian Journal, 2012

The hydrophobic ionic liquid N-butyl-N-methylpyrrolidinium bis((trifluoromethyl)sulfonyl)amide (B... more The hydrophobic ionic liquid N-butyl-N-methylpyrrolidinium bis((trifluoromethyl)sulfonyl)amide (BMP-TFSA IL), which contains a series of flexible ionophores of polypyridine-type small molecules or two rigid ionophores of peripherally pyridine-modified PAMAM dendrimers, was used to extract cupric ions from aqueous solutions. The polypyridine-type ionophores show good selectivity toward cupric ions at pH 2. The selectivity is affected by the spacing between the two amino groups. However, the pyridine-modified dendrimers showed poor selectivity, although their extraction efficiency still depended on the pH of the aqueous solution. The ionic liquids that contained small molecular ionophores and their dendrimer analogs were reused after acid washing or electrochemical reduction. During acid washing, the nitrogen atoms of the ionophores were protonated to release the cupric ions into the aqueous phase, and the copper atoms were deposited onto the electrode surface during the electrochemical reduction accompanied by the regeneration of the ionophores.

Electrochemistry Communications, 2013

RSC Advances, 2016

Beaded aluminum wires with tunable physical morphology were prepared from a chloroaluminate ionic... more Beaded aluminum wires with tunable physical morphology were prepared from a chloroaluminate ionic liquid using a template-free square-wave pulse potential electrodeposition method with various pulse potential and duration combinations.