Oxidation Mechanism of Hypophosphite
- 1999年第5卷 
对次磷酸盐体系循环伏安曲线－０．４Ｖ（ＳＣＥ）处氧化峰（Ⅱ峰）的特性及本质进行深入研究．结果表明，Ⅱ峰与Ⅰ峰直接相关，对应于活性吸附态的偏亚磷酸根氧化生成磷酸根的电极过程，Ⅱ峰是偏亚磷酸根脱出的Ｈ－ａｄｓ离子在电极上发生氧化的结果．确定了吸附态偏亚磷酸根转变为惰性亚磷酸根反应的控速步骤为偏亚磷酸的脱附过程，并估算了脱附速度常数．最后给出可能的吸附态偏磷酸根氧化生成磷酸根的电极历程及总的次磷酸根氧化机制模型．There exist two oxidation current peaks on the anodic polarization curve between -0.7 V and 0 V(SCE) in Na_hypophosphite solution. Peak Ⅰ (-0.55 V, SCE) , which represents the oxidation process from H 2PO - 2 to H 2PO - 3, has been studied previously. Peak Ⅱ, which is located at the potential about -0.4 V(SCE), is investigated emphatically in this paper. The results show that, peak Ⅰ and Ⅱ are corresponding to two successive steps in oxidation process of H 2PO - 2, i.e. peak Ⅱ corresponds to the oxidation process of adsorped (HPO 2) ads , an intermediate product of electrode reaction of peak Ⅰ, to PO 3- 4. The rate limiting step in the electrode process from (HPO 2) ads to HPO 2- 3 is the desorption of (HPO 2) ads , and the desorption rate constant is estimated as 2.32±0.20 s -1 . A new schematic of oxidation process of hypophosphite is proposed.