A nickel salen complex was encapsulated in the supercages of nanozeolite NaA,LTA(linde type A)structure,using the flexible ligand method.The electrochemical behavior and electrocatalytic activity of a carbon paste ele...A nickel salen complex was encapsulated in the supercages of nanozeolite NaA,LTA(linde type A)structure,using the flexible ligand method.The electrochemical behavior and electrocatalytic activity of a carbon paste electrode(CPE)modified with Ni(II)‐Salen‐A(Ni(II)‐SalenA/CPE)for hydrazine oxidation in0.1mol/L NaOH solution were investigated by cyclic voltammetry,chronoamperometry,and chronocoulometry.First,organic‐template‐free synthesis of nanozeolite LTA was performed and the obtained material was characterized by various techniques.The average particle size of the LTA crystals was estimated to be56.1and72nm by X‐ray diffraction and particle size analysis,respectively.The electron transfer coefficient was found to be0.64and the catalytic rate constant for oxidation of hydrazine at the redox sites of Ni(II)‐SalenA/CPE was found to be1.03×105cm3/(mol·s).Investigation of the electrocatalytic mechanism suggested that oxidation of hydrazine occurred through reaction with Ni3+(Salen)O(OH)and also direct electrooxidation.The anodic peak currents revealed a linear dependence on the square root of the scan rate,indicating a diffusion‐controlled process,and the diffusion coefficient of hydrazine was found to be1.18×10?7cm2/s.The results indicated that Ni(II)‐SalenA/CPE displays good electrocatalytic activity toward hydrazine oxidation owing to the porous structure of nanozeolite LTA and the Ni(II)‐Salen complex.Finally,the general reaction mechanism for the electrooxidation of hydrazine on Ni(II)‐SalenA/CPE in alkaline solution involves the transfer of four electrons,in which the first electron transfer reaction acts as the rate‐limiting step followed by a three‐electron process to generate environmentally friendly nitrogen and water as final products.展开更多
The polymer of complex [Ni（salen）], （N,N＇-ethylenebis （salicylideneaminato） nickel（U））, was prepared on graphite electrode by the route of linear sweep potential method. The nano-micro sheaf/wire structures o...The polymer of complex [Ni（salen）], （N,N＇-ethylenebis （salicylideneaminato） nickel（U））, was prepared on graphite electrode by the route of linear sweep potential method. The nano-micro sheaf/wire structures of poly[Ni（salen）] have been obtained by adjusting the polymerization sweep rate of 5, 20 and 40 mV.s-1. The polymer prepared at 20 mV.s-1 had nanoscaled wire structure of ca. 100 nm in diameter. The good electrochemical reversibility of poly[Ni（salen）] was investigated by cyclic voltammetry and galvanostatic test in 1.0 mol/L Et3MeNBF4/acetonitrile solution. The initial specific gravimetric capacitance of poly[Ni（salen）] at the current density of 0.1 mA·cm-2 reached 270.2 F·g-1, however, the cycle stability needs to be improved.展开更多
文摘A nickel salen complex was encapsulated in the supercages of nanozeolite NaA,LTA(linde type A)structure,using the flexible ligand method.The electrochemical behavior and electrocatalytic activity of a carbon paste electrode(CPE)modified with Ni(II)‐Salen‐A(Ni(II)‐SalenA/CPE)for hydrazine oxidation in0.1mol/L NaOH solution were investigated by cyclic voltammetry,chronoamperometry,and chronocoulometry.First,organic‐template‐free synthesis of nanozeolite LTA was performed and the obtained material was characterized by various techniques.The average particle size of the LTA crystals was estimated to be56.1and72nm by X‐ray diffraction and particle size analysis,respectively.The electron transfer coefficient was found to be0.64and the catalytic rate constant for oxidation of hydrazine at the redox sites of Ni(II)‐SalenA/CPE was found to be1.03×105cm3/(mol·s).Investigation of the electrocatalytic mechanism suggested that oxidation of hydrazine occurred through reaction with Ni3+(Salen)O(OH)and also direct electrooxidation.The anodic peak currents revealed a linear dependence on the square root of the scan rate,indicating a diffusion‐controlled process,and the diffusion coefficient of hydrazine was found to be1.18×10?7cm2/s.The results indicated that Ni(II)‐SalenA/CPE displays good electrocatalytic activity toward hydrazine oxidation owing to the porous structure of nanozeolite LTA and the Ni(II)‐Salen complex.Finally,the general reaction mechanism for the electrooxidation of hydrazine on Ni(II)‐SalenA/CPE in alkaline solution involves the transfer of four electrons,in which the first electron transfer reaction acts as the rate‐limiting step followed by a three‐electron process to generate environmentally friendly nitrogen and water as final products.
基金supported by the Beijing Natural Science Foundation of China(No.2093039)Program for New Century Excellent Talents in Universities(NECT).
文摘The polymer of complex [Ni（salen）], （N,N＇-ethylenebis （salicylideneaminato） nickel（U））, was prepared on graphite electrode by the route of linear sweep potential method. The nano-micro sheaf/wire structures of poly[Ni（salen）] have been obtained by adjusting the polymerization sweep rate of 5, 20 and 40 mV.s-1. The polymer prepared at 20 mV.s-1 had nanoscaled wire structure of ca. 100 nm in diameter. The good electrochemical reversibility of poly[Ni（salen）] was investigated by cyclic voltammetry and galvanostatic test in 1.0 mol/L Et3MeNBF4/acetonitrile solution. The initial specific gravimetric capacitance of poly[Ni（salen）] at the current density of 0.1 mA·cm-2 reached 270.2 F·g-1, however, the cycle stability needs to be improved.
