Structure-Controlled Rh/Sn/Pt Ternary Catalysts for Complete Oxidation Reaction of Ethanol to Carbon Dioxide

摘要

Sn was deposited on a Pt electrode (Sn/Pt) with the coverage of 0.23, following by the Rh deposition by different methods: random arrangement (Rh/Sn/Pt(1)) and controlled arrangement (Rh/Sn/Pt(2)). Inductive coupled plasma mass spectroscopy (ICP-MS) was used to evaluate the Sn/Rh molar ratio, which was 3 for Rh/Sn/Pt(1) and 6 for Rh/Sn/Pt(2). The ethanol oxidation reaction (EOR) activity of Rh/Sn/Pt(2) was similar to that of Sn/Pt, which was ca. 3 times as high as that of Pt. However, the EOR activity of Rh/Sn/Pt(1) was ca. 1.5 times as high as that of Sn/Pt. The onset potential of EOR for the Sn/Pt and Rh/Sn/Pt electrodes was 0.1 V and 0.2 V lower than that for the Pt electrode, respectively. The in-situ infrared reflection absorption spectroscopy (IRRAS) exhibited that, for Rh/Sn/Pt(1), the formation of acetic acid was predominant over CO_2, whereas Rh/Sn/Pt(2) with lower EOR activity was superior in CO_2 selectivity to Rh/Sn/Pt(1).