Internal CClF was conducted directly in the EC-MS cell. The system settings and cell configuration, as well as reference and counter electrodes were the same as in CORR, whereas a Pt stub (>99.999%, GoodFellow) was employed as the working electrode. Pt was used because its capability of doing electrochemical Cl2 evolution has been widely demonstrated by previous studies , , . Although not as active as Ru or Ir , Pt is more stable. Since Pt could produce sufficient and consistent Cl2 for inspecting its potential Chem-I influences, it was chosen as the working electrode.