Electrooxidation of Ethanol on Highly Preferred Orientation (220) Nickel Electrode in Alkaline Media
- 化学化工－已发表论文 
采用循环伏安法和现场红外反射光谱研究了1.0mol/LNaOH溶液中高择优取向镍电极上乙醇的电催化氧化活性及机理。结果表明,高择优取向镍电极对乙醇的电氧化有较高的催化作用,氧化的产物为CH3COO-;采用稳态法推导出乙醇的电氧化动力学方程,运用稳态极化曲线测定了其电氧化过程的动力学参数,高择优取向(220)镍电极在碱性溶液中形成的Ni(Ⅲ)与乙醇的反应速率常数k2=5.7×10-6L/(mol·s),Ni(Ⅱ)氧化为Ni(Ⅲ)的反应速度常数k1=4.9×10-13exp(0.52FE/RT),Ni(Ⅲ)还原为Ni(Ⅱ)的反应速度常数k-1=3.7×10-4exp(-0.48FE/RT)。Ni electrodes with highly preferred orentation (220) were obtained by means of potentiostatic electrodeposition in the solution containing 1.0 mol/L NiSO_ 4 and 0.5 mol/L H_ 3BO_ 3. The Ni electrode deposited at -1.25 V for 60 min was examined with X-ray diffraction. The result shows that Ni electrode exhibits highly preferred orientation with a texture degree of 92%. The mechanism and catalytic activity of ethanol oxidation on the highly preferred orientation (220) Ni electrode were studied with cyclic voltammetry and in situ FTIR spectroscopy. The results show that the Ni electrode has electrocatalytic activity for the oxdation of ethanol. The main product of ethanol oxidation on the Ni electrode is CH_ 3COO -. The kinetic equation of ethanol electrooxidation was derived. The kinetic parameters were determined with the polarization curves. The rate constant k_1 for the oxidation of Ni(Ⅱ) to Ni(Ⅲ) is 4.9×10 -13exp(0.52FE/RT) and the rate constant (k_2) for the oxidation of ethanol by Ni(Ⅲ) is 5.7×10 -6 L/(mol·s).