Electroreduction of nitrous oxide on platinum and palladium: Toward selective catalysts for methanol–nitrous oxide mixed-reactant fuel cells

• Published in: Electrochimica acta Vol. 56; no. 14; pp. 5238 - 5244
• Main Authors: Aziznia, Amin, Bonakdarpour, Arman, Gyenge, Előd L., Oloman, Colin W.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 30.05.2011; Elsevier
• Subjects: Applied sciences; Electrode kinetics; Electrodes; Electrowinning; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; Methanol oxidation; Methyl alcohol; Mixed reactant fuel cell; N2O reduction; Nitrous oxides; Oxidation; Palladium; Platinum; Reduction; Electrode kinetics; N2O reduction; Methanol oxidation; Mixed reactant fuel cell; Basic solution; Polycrystal; Temperature effect; Transition metal; Palladium; N; Operating conditions; Electrodes; Chemical reduction; Electrocatalysis; O reduction; Medium effect; Platinum; Reaction mechanism; Oxidation; Nitrous oxide; Kinetics; Nitrogen protoxide; Electrochemical reaction; Platinoid; Methanol
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2011.03.023

► Detailed study of N2O electroreduction in 0.1 M NaOH on Pd and Pt in the presence and absence of methanol. ► Pd is more active for N2O electroreduction than Pt and its activity is not significantly affected by the presence of 1 M methanol in the electrolyte. ► Pt retains selectivity toward methanol oxidation in the presence of N2O. The kinetics of N2O electroreduction in the absence and presence of methanol was studied between 295 and 333K on polycrystalline Pt and Pd electrodes in 0.1M NaOH. In the absence of methanol the reduction of N2O on Pd is more facile than on Pt as shown by the approximately four times lower apparent activation energy and lower Tafel slope (Pt: 0.111±0.019Vdec−1, Pd: 0.084±0.007Vdec−1 at 295K). Two different electroreduction mechanisms are proposed for Pt and Pd with and without participation of underpotential deposited hydrogen, respectively. The selectivity of Pt and Pd electrodes toward both N2O electroreduction and methanol (0.5 and 1M) oxidation at 295K was also investigated. Pt based electrocatalysts are promising candidates for the anode of a mixed reactant CH3OH–N2O fuel cell due to inhibition of N2O reduction by chemisorbed methanol. Pd on the other hand is a selective cathode electrocatalyst since N2O reduction takes place fairly actively in the presence of 1M methanol, while methanol oxidation is inhibited.