Glycerol electro-oxidation on a carbon-supported platinum catalyst at intermediate temperatures

• Published in: Journal of power sources 2013-03, Vol.225, p.141-149
• Main Authors: Ishiyama, Keisuke, Kosaka, Fumihiko, Shimada, Iori, Oshima, Yoshito, Otomo, Junichiro
• Format: Article
• Language: English
• Subjects: Alternative fuels. Production and utilization; Applied sciences; Catalysis; Catalysts: preparations and properties; Cesium dihydrogen phosphate; Chemistry; Direct alcohol fuel cell; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electro-oxidation; Electrochemical conversion: primary and secondary batteries, fuel cells; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; Fuels; General and physical chemistry; Glycerol; Hydrogen; Intermediate temperature; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2012.10.035

The electro-oxidation of glycerol on a carbon-supported platinum catalyst (Pt/C) in combination with a reaction products analysis was investigated at intermediate temperatures (235–260 °C) using a single cell with a CsH2PO4 proton conducting solid electrolyte. A high current density was achieved. The main products were H2, CO2 and CO but the formation of C2 compounds, such as glycolic acid and ethane, was also observed. In addition, several C3 compounds were detected as minor products. A reaction products analysis revealed that the C–C bond dissociation ratio of glycerol was 70–80% at both low and high potentials (>200 mV vs. reversible hydrogen electrode) at 250 °C, suggesting that rapid dissociation occurs on Pt/C. The reaction products analysis also suggested that hydrogen production via thermal decomposition and/or steam reforming of glycerol (indirect path) and direct electro-oxidation of glycerol (direct path) proceed in parallel. More detailed reaction paths involving C1, C2 and C3 reaction products are discussed as well as the possible rate-determining step in glycerol electro-oxidation at intermediate temperatures. ► A high oxidation current in glycerol electro-oxidation was observed at 250 °C. ► High selectivity for CO2 production was obtained at 250 °C. ► C–C bond dissociation ratio reached 70–80% at both low and high potentials. ► Stable operation during glycerol electro-oxidation at around 250 °C requires a high S/C ratio. ► The present observations provide strategies for the effective operation of DAFCs.