The effect of metal solution contaminants on the platinum electro-catalyst during methanol oxidation and oxygen reduction reactions

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Switzerland), 2020-04, Vol.862, p.113997, Article 113997
• Main Authors: Jalilpour, Soghra, Bock, Christina, MacDougall, Barry R., Hall, David S.
• Format: Article
• Language: English
• Subjects: Cation/anion impurity; Cobalt/nickel/zinc UPD; Fuel cells; MOR; ORR
• ISSN: 1572-6657; 1873-2569
• DOI: 10.1016/j.jelechem.2020.113997

Understanding the effect of metal solution contaminants on the methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) activities of direct methanol fuel cells (DMFCs) is critical in the enhancement of this technology. In this study, the effect of various concentrations of metal salt solutions (i.e., Co, Ni and Zn with sulfate and nitrate as counter-anions) on polycrystalline Pt and PtxRuy electro-catalytic activities during MOR and ORR are systematically investigated. The results show a decrease in MOR and ORR activities as the concentration of metal salt solutions increased. The influence of counter-anions (i.e., NO3− and SO42−) adsorption on the Pt electro-catalyst activity was further investigated. The results showed that a combined effect of adsorbed counter-anions as well as hydrated metal cations may be responsible for the decrease in the electro-catalytic activity of Pt during the MOR and ORR. •The effect of metal solution contaminants on electro-catalytic activities of Pt and PtxRuy was investigated.•The UPD of metal ((Ni2+, Co2+and Zn2+)) on Pt was obtained in the presence of metal sulfate and zinc nitrate solutions.•A partial UPD of Ni2+ and Co2+ (from metal nitrate) on Pt surface may inhibit nitrate anion reduction.•Decrease in MOR and ORR activities was observed in the presence of high concentration of metal solution contaminants.•A combined effect of adsorbed counter-anions and hydrated metal cations may inhibit the MOR and ORR activities.