A dc power supply AE-8270 (Atto Co., Japan) or MP-7612D (System Instruments Co., Ltd., Japan) was used to provide a constant voltage across the anode and cathode during the experiment.
A dc power supply AE-8270 (Atto Co., Japan) or MP-7612D (System Instruments Co., Ltd., Japan) was used to provide a constant voltage across the anode and cathode during the experiment.