光电化学反应的催化I.大颗粒金岛对n-TiO2电极上光电化学过程的催化作用

用溅射、光还原及电沉积法在n-TiO2单晶电极表面上形成了大颗粒金岛,测量了这些电极和纯金电极在H2SO4溶液以及含有Fe[3+]/Fe[2+]的酸溶液中的光电化学极化行为。通过分析和比较这些曲线,确定了大颗粒金岛与n-TiO2单晶的接触具有欧姆结性质。并借助于可换盘旋转环盘电极,在含Ce[3+]的酸溶液中测量了裸TiO2电极及载金TiO2电极上Ce[3+]的竞争光电化学氧化。证实了以大岛形式在TiO2电极表面上分布的催化剂只能催化暗反应,而不能催化光电化学反应。

The catalysis of photoelectrochemical reactions I. The catalytic action of large gold islands on photoelectrochemical reactions at n-TiO2 electrode

Large Au islands were deposited on TiO2 single crystal electrodes by sputtering, photoredn. and electrodeposition. The photoelectrochem. behavior of Au coated semiconductor electrodes and pure Au electrodes was measured in H2SO4 and in an acid solution containing Fe3+/Fe2+. As the result of anal. of these polarization curves it was found that the contact between Au particles and the semiconductor surface is mainly ohmic in nature. The catalytic behavior of Au islands on the competitive photooxidn. of Ce3+ and H2O were studied by using rotating ring disk electrode with interchangeable disk. Au particles in the form of large islands could only catalyze dark (electrochem.) reactions, but not photoelectrochem. reactions.