温度对Cr_2O_7^(2-)阳极形成过程的影响

EFFECT OF TEMPERATURE ON THE PROCESS OF ANODIC FORMATION OF Cr_2O_7^(2- )

用分解极化曲线法研究了在 0 .1 mol/ L Cr2 ( SO4) 3+1 mol/ L Na2 SO4+0 .2 mol/ L H2 SO4溶液中 Pt和Pb O2 电极上 Cr2 O2 - 7阳极形成和 O2 析出过程中温度的影响 .实验结果表明 ,在 1 .95V下 ,Pt电极上 O2 和Cr2 O2 - 7的表观活化能分别为 57.4 k J/ mol和 61 .3 k J/ mol;Pb O2 电极上 O2 和 Cr2 O2 - 7表观活化能分别为 4 0 .2 k J/mol和 4 6.2 k J/ mol.温度对于 Cr2 O2 - 7形成的加速作用要大于对 O2 析出的加速作用 ,当温度升高时 ,使 Cr2 O2 - 7的电流效率提高 .固定温度和固定电位下 Pb O2 上 O2 析出速度较之 Pt电极上增加不大 ,但 Cr2 O2 - 7形成速度远比 Pt电极上大 ,可见 Pb O2 电极对于 Cr2 O2 - 7的阳极形成具有较高的催化活性 .

The influence of temperature on the Cr 2O 2- 7 anodic formation and O 2anodic evolution at Pt and PbO 2 electrodes were investigated in mixed H 2SO 4 Na 2SO 4 solutions. It was found that the catalytic activities for Cr 2O 2- 7 anodic formation reaction are relatively high at PbO 2 electrode and that the activity of PbO 2 electrode is higher than that of Pt electrode. The steady state polarization curves for Cr 2O 2- 7 and O 2 at 20, 30, 40, 50 and 60°C, and the activation energy of O 2 evolution and Cr 2O 2- 7 anodic formation reaction are reported.