Influence of different morphologies on the catalytic activity of Pt-Pd nanostructures for methanol oxidation

Author(s)

Santos, Dara S. ; Trench, Aline B. ; Costa, Ivani M. ; Santos, Mauro C. ; Eguiluz, Katlin I. B. ; Salazar-Banda, Giancarlo R.

• Document type: Journal article
• Source: Electrochimica Acta; v. 508, p. 16-pg., 2024-10-25.

Abstract

Developing efficient and durable catalysts for methanol oxidation in acidic media remains a significant challenge in electrochemical energy conversion. This study addresses this issue by synthesizing Pt-Pd bimetallic electrocatalysts with different morphologies, including nanowires, core-shell nanoparticles, and core-shell nanowires, and evaluating their catalytic activities. The electrocatalysts were prepared via chemical reduction of metal precursors using formic acid as a reducing agent. X-ray diffraction analysis revealed distortions in the lattice parameters of the nanostructured bimetallic catalysts, and STEM/EDX analysis confirmed the formation of the different morphologies on the carbon support. Electrochemical assessments showed that the bimetallic catalysts exhibited superior catalytic activities to nanostructured Pt/C catalysts. The Pd@Pt/C core-shell nanowires displayed the highest catalytic efficiency, with the lowest methanol oxidation onset potential (468 mV) and the highest mass and specific activities. Electrochemical impedance measurements revealed the lowest charge transfer resistance value for the Pd@Pt/C core-shell nanowires. Chronoamperometric tests further indicated that the Pd@Pt/C core-shell nanowires catalyst exhibited superior tolerance to inactivation by reaction intermediates, achieving mass and specific activities approximately twice as high as those of the Pt/C catalyst. The enhanced catalytic performance of the Pd@Pt/C core-shell nanowires was attributed to the synergistic effects of the two morphologies that alter the electronic and geometric structures of the Pt within the catalyst. (AU)

• FAPESP's process: 21/14394-7 - Use of Vulcan XC-72 carbon modified with fluorine and/or cerium doped niobium nanostructures in the electrogeneration of H2O2 for degradation of endocrine disruptors by advanced electrochemical oxidative processes
• Grantee: Aline Barrios Trench
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 22/15252-4 - Nanostructured electrocatalysts for application in direct alkaline-acid fuel cells of glycerol
• Grantee: Mauro Coelho dos Santos
• Support Opportunities: Program for Research on Bioenergy (BIOEN) - Regular Program Grants
• FAPESP's process: 22/12895-1 - Advanced processes for the degradation of emerging pollutants: catalytic materials, electroanalytical sensors and scientific dissemination
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Research Projects - Thematic Grants