PdxNby electrocatalysts for DEFC in alkaline medium: Stability, selectivity and mechanism for FOR

Author(s)

Souza, F. Moura ^[1] ; Nandenha, J. ^[2] ; Batista, B. L. ^[1] ; Oliveira, V. H. A. ^[1] ; Pinheiro, V. S. ^[1] ; Parreira, L. S. ^[3] ; Neto, A. O. ^[2] ; Santos, M. C. ^[1]

Affiliation

^[1] Univ Fed Abc, CCNH, LEMN, Rua Santa Adelia 166, BR-09210170 Santo Andre, SP - Brazil

^[2] CNEN SP, IPEN, Ave Prof Lineu Prestes 2242, Cidade Univ, BR-05508000 Sao Paulo, SP - Brazil

^[3] Univ Sao Paulo, IQ, Ave Prof Lineu Prestes 748, Cidade Univ, BR-05508000 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: INTERNATIONAL JOURNAL OF HYDROGEN ENERGY; v. 43, n. 9, p. 4505-4516, MAR 1 2018.
• Web of Science Citations: 13

Abstract

PdxNby/C binary electrocatalysts supported on Vulcan carbon XC72 were prepared by the sol-gel method. The materials are characterized by transmission electron microscopy, Xray diffraction analysis, inductively coupled plasma-mass spectrometry and contact angle measurements. The electrocatalytic activity for ethanol electrooxidation reaction was studied by cyclic voltammetry, chronoamperometry, Tafel slope and accelerated durability testing. The direct ethanol. performance and the products after the experiments were studied by Fourier transform infrared spectroscopy. Pd1Nb1/C (50:50 wt%) shows superior activity for ethanol oxidation compared to the other electrocatalysts prepared in this work. All electrocatalysts containing Nb show the highest current exchange density. The Tafel slope results suggest that the Nb modified the Pd-electrocatalyst to obtain a reaction path with high selectivity with only a single determining step with low production of the intermediates for the ethanol oxidation reaction. The best performance is obtained using Pd1Nb1/C 18.11 mW cm(-2). The Pd1Nb1/C electrocatalyst displays the highest production of CO2 and the lowest production of acetaldehyde. Pd1Nb1/C shows the highest peak current density during 1000 cycles of the experiment and the lowest mass loss of Pd after the cycling test. We find that the Nb modifies the Pd electrocatalysts from the bifunctional mechanism and reduces the loss of Pd during the accelerated durability test. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 16/00819-8 - Controlled Synthesis of Nanomaterials based on Pd and Pt: Electrocatalytic Activity and Stability
• Grantee: Luanna Silveira Parreira
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 15/10314-8 - Nanostructures for Phenol, Ciprofloxacin and 17±-ethinylestradiol Degradation
• Grantee: Mauro Coelho dos Santos
• Support Opportunities: Regular Research Grants
• FAPESP's process: 17/21846-6 - Nanostructures for environmental remediation and power generation from renewable sources
• Grantee: Mauro Coelho dos Santos
• Support Opportunities: Program for Research on Bioenergy (BIOEN) - Regular Program Grants