Apparent enthalpies of activation for oxygen reduction at Pt3Co electrode in alkaline solution
Апстракт
Oxygen reduction (OR) at a Pt3Co alloy electrode has been examined in alkaline solutions of different pH's in the temperature range from 274 to 313 K. At all temperatures, two distinct E-log j rep-ions are observed. At low current densities (cd), Tafel slopes are close to -2.3 RT/F while at high current densities they are close to -2 x 2.3RT/F. The Tafel slopes at all pH values closely follow the kconventional temperature dependence with beta = 1/2. In addition, to confirm the mechanism in the two cd regions, the apparent enthalpies of activation at the selected potentials are calculated in both low and high cd regions at different pH. Although the relation DeltaH(a,J c.d)* gt DeltaH(a,h .c.d)(not equal) was found to be valid. it is concluded that at every pH, at the zero Galvani potential difference, the enthalples of activation are identical, and the rate determining step of OR reaction is the same in both cd regions. The changes in the Tafel slopes arise from different adsorption ...conditions of reaction intermediates in these regions as previously suggested [1].
Кључне речи:
enthalpy of activation / oxygen reduction / Pt-Co alloy / reaction mechanismИзвор:
Materials Science Forum, 2004, 453-454, 109-114Издавач:
- Progress in Advanced Materials and Processes: Proceedings of the Fifth Jugoslav Materials Research Society, YUCOMAT V
Институција/група
Tehnološko-metalurški fakultetTY - JOUR AU - Obradović, Maja AU - Grgur, Branimir AU - Vračar, Ljiljana M. PY - 2004 UR - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/596 AB - Oxygen reduction (OR) at a Pt3Co alloy electrode has been examined in alkaline solutions of different pH's in the temperature range from 274 to 313 K. At all temperatures, two distinct E-log j rep-ions are observed. At low current densities (cd), Tafel slopes are close to -2.3 RT/F while at high current densities they are close to -2 x 2.3RT/F. The Tafel slopes at all pH values closely follow the kconventional temperature dependence with beta = 1/2. In addition, to confirm the mechanism in the two cd regions, the apparent enthalpies of activation at the selected potentials are calculated in both low and high cd regions at different pH. Although the relation DeltaH(a,J c.d)* gt DeltaH(a,h .c.d)(not equal) was found to be valid. it is concluded that at every pH, at the zero Galvani potential difference, the enthalples of activation are identical, and the rate determining step of OR reaction is the same in both cd regions. The changes in the Tafel slopes arise from different adsorption conditions of reaction intermediates in these regions as previously suggested [1]. PB - Progress in Advanced Materials and Processes: Proceedings of the Fifth Jugoslav Materials Research Society, YUCOMAT V T2 - Materials Science Forum T1 - Apparent enthalpies of activation for oxygen reduction at Pt3Co electrode in alkaline solution EP - 114 SP - 109 VL - 453-454 UR - https://hdl.handle.net/21.15107/rcub_technorep_596 ER -
@article{ author = "Obradović, Maja and Grgur, Branimir and Vračar, Ljiljana M.", year = "2004", abstract = "Oxygen reduction (OR) at a Pt3Co alloy electrode has been examined in alkaline solutions of different pH's in the temperature range from 274 to 313 K. At all temperatures, two distinct E-log j rep-ions are observed. At low current densities (cd), Tafel slopes are close to -2.3 RT/F while at high current densities they are close to -2 x 2.3RT/F. The Tafel slopes at all pH values closely follow the kconventional temperature dependence with beta = 1/2. In addition, to confirm the mechanism in the two cd regions, the apparent enthalpies of activation at the selected potentials are calculated in both low and high cd regions at different pH. Although the relation DeltaH(a,J c.d)* gt DeltaH(a,h .c.d)(not equal) was found to be valid. it is concluded that at every pH, at the zero Galvani potential difference, the enthalples of activation are identical, and the rate determining step of OR reaction is the same in both cd regions. The changes in the Tafel slopes arise from different adsorption conditions of reaction intermediates in these regions as previously suggested [1].", publisher = "Progress in Advanced Materials and Processes: Proceedings of the Fifth Jugoslav Materials Research Society, YUCOMAT V", journal = "Materials Science Forum", title = "Apparent enthalpies of activation for oxygen reduction at Pt3Co electrode in alkaline solution", pages = "114-109", volume = "453-454", url = "https://hdl.handle.net/21.15107/rcub_technorep_596" }
Obradović, M., Grgur, B.,& Vračar, L. M.. (2004). Apparent enthalpies of activation for oxygen reduction at Pt3Co electrode in alkaline solution. in Materials Science Forum Progress in Advanced Materials and Processes: Proceedings of the Fifth Jugoslav Materials Research Society, YUCOMAT V., 453-454, 109-114. https://hdl.handle.net/21.15107/rcub_technorep_596
Obradović M, Grgur B, Vračar LM. Apparent enthalpies of activation for oxygen reduction at Pt3Co electrode in alkaline solution. in Materials Science Forum. 2004;453-454:109-114. https://hdl.handle.net/21.15107/rcub_technorep_596 .
Obradović, Maja, Grgur, Branimir, Vračar, Ljiljana M., "Apparent enthalpies of activation for oxygen reduction at Pt3Co electrode in alkaline solution" in Materials Science Forum, 453-454 (2004):109-114, https://hdl.handle.net/21.15107/rcub_technorep_596 .