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本文对钒(Ⅴ)在磷酸盐体系中过氧化氢的极谱催化波进行了研究。确定了催化波的分析条件为0.2MNaH_2PO_4,0.05MH_2O_2,pH=5底液中,钒(Ⅴ)浓度由1×10~(-8)—7×10~(-7)M之间与电流呈直线关系。推导了利用催化电流求电极活性络合物组成的关系式为,1/i=1/imax+1/βimax·1/[H_PO_4~-]~(n■)并求得电极活性络合物组成为H_2VO_5H_2PO_4~(2-),相应条件稳定常数β=25.2。同时求得在砷酸盐底液中电极活性络合物组成为H_2VO_5H_2AsO_4~(2-),相应β=28.3。另外由汞柱高对催化电流影响、电毛细管曲线、i-t曲线、三角波扫描图形等实验判断.认为催化电流是由VO_3·H_2PO_4~(2-)在电极上被吸附,因而催化了过氧化络合物的形成和在电极上放电。
In this paper, polarographic catalysis wave of hydrogen peroxide in vanadium (Ⅴ) system has been studied. The analytical conditions of the catalytic wave were determined as follows: the concentration of vanadium (V) was between 1 × 10 -8 ~ -7 × 10 -7 M and the current was in the range of 0.2M NaH 2 PO 4, 0.05MH 2 O 2 and pH = 5. Straight line relationship. The relationship between the composition of the active complex and the active complex of the electrode was derived by using a catalytic current as follows: 1 / i = 1 / imax + 1 / βimax · 1 / [H_PO_4 ~ -] ~ (n ■) Is H_2VO_5H_2PO_4 ~ (2-), the corresponding condition of stability constant β = 25.2. At the same time, the composition of the electrode active complex in the arsenate bottom solution was found to be H 2 VO 5 H 2 AsO 4 ~ (2-), corresponding to β = 28.3. In addition, the experimental results show that the catalytic current is adsorbed on the electrode by VO 3 · H 2 PO 4 ~ (2-) and thus catalyzes the peroxidation complexation The formation and discharge of the electrode.