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在NaAc-HAc介质(pH5.3)中,铬黑T(EBT)和Ga(Ⅲ)-EBT分别于-0.40V和-0.63V产生的峰电流具有吸附特性,均为不可逆电极反应过程。测得EBT和Ga(Ⅲ)-EBT的电子传递系数(α)分别为0.38和0.58,电子转移数(n)和质子数(m)均为2°EBT在电极表面的饱和吸附量(Г_0~S)为5.6×10~(-10)mol/cm~2。在pH4.8～5.6间,EBT(H_3L)主要以H_2L~-形式存在;Ga(Ⅲ)与不同浓度的EBT形成组分比分别为1:1和1:2:两种络合物,相应累积稳定常数K_1=7.2×10~(12),K_2=5.3×10~(25)。提出了它们的电极反应机理,并对温度试验过程中产生的“热色(电)效应”进行了探讨。
In NaAc-HAc medium (pH5.3), the peak current generated by CrTi and Ga (III) -EBT at -0.40V and -0.63V, respectively, has the adsorption characteristics, which are all irreversible electrode reactions. The electron transfer coefficients (α) of EBT and Ga (Ⅲ) -EBT were 0.38 and 0.58, respectively. The electron transfer number (n) and proton number (m) were 2 ° EBT adsorption capacity on the electrode surface (Γ 0 ~ S) is 5.6 × 10 ~ (-10) mol / cm ~ 2. At pH4.8 ~ 5.6, EBT (H_3L) mainly exists in the form of H_2L ~ -. The composition ratios of Ga (Ⅲ) to different concentrations of EBT are 1: 1 and 1: 2: The cumulative stability constants K_1 = 7.2 × 10 ~ (12), K_2 = 5.3 × 10 ~ (25). Their electrode reaction mechanism was put forward and the “thermochromic effect” produced during the temperature test was also discussed.