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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Oxidation of ammonia using PtRh/C electrocatalysts: Fuel cell and electrochemical evaluation

Full text
Author(s):
Assumpcao, Monica H. M. T. [1] ; Piasentin, Ricardo M. [1] ; Hammer, Peter [2] ; De Souza, Rodrigo F. B. [1] ; Buzzo, Guilherme S. [1] ; Santos, Mauro C. [3] ; Spinace, Estevam V. [1] ; Neto, Almir O. [1] ; Silva, Julio Cesar M. [1]
Total Authors: 9
Affiliation:
[1] IPEN CNEN SP, Inst Pesquisas Energet & Nucl, BR-05508900 Sao Paulo, SP - Brazil
[2] UNESP Univ Estado Sao Paulo, Inst Quim, BR-14801970 Araraquara, SP - Brazil
[3] Univ Fed ABC, Ctr Ciencias Nat & Humanas, Lab Eletroquim & Mat Nanoestruturados, BR-09210170 Santo Andre, SP - Brazil
Total Affiliations: 3
Document type: Journal article
Source: APPLIED CATALYSIS B-ENVIRONMENTAL; v. 174, p. 136-144, SEP 2015.
Web of Science Citations: 30
Abstract

This study reports on the use of PtRh/C electrocatalysts prepared by the borohydride reduction method with different Pt:Rh atomic ratios: (90:10,70:30 and 50:50) which was investigated toward the ammonia electro-oxidation considering electrochemical and also direct ammonia fuel cell (DAFC) experiments. The DAFC experiments were conducted using different proportions of NH4OH and KOH as fuels. X-ray diffraction showed the formation of PtRh alloy while transmission electron micrographs showed the particles sizes between 4.1 and 4.5 nm. Among the different NH4OH and KOH concentrations the combination of 3 mol L-1 NH4OH and 3 mol L-1 KOH was the most favorable due to the higher KOH concentration, which increased the electrolyte conductivity, thus, improving the ammonia oxidation. Moreover, among the PtRh/C electrocatalysts the Pt:Rh ratio of 90:10 showed to be the best suited one since it showed a power density almost 60% higher than Pt. X-ray photoelectron spectroscopy results revealed for this catalyst that the nanoparticles contain a high proportion of metallic Pt and Rh phases, supporting the alloy formation between Pt and Rh. The improved fuel cell efficiency can be related to the combination of different effects: the alloy formation between Pt and Rh (electronic effect), suppressing the adsorption strength of poisonous intermediates, and a synergic effect between Pt and Rh at this composition. (C) 2015 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 12/22731-4 - Electrocatalysts SUPPORTED IN DIFFERENT SUBSTRATES prepared by codeposition electrochemistry for direct liquid fuel cell (methanol , ethanol and formic acidic)
Grantee:Guilherme Soares Buzzo
Support Opportunities: Scholarships in Brazil - Post-Doctoral
FAPESP's process: 11/18246-0 - Preparation of PD binary and ternary electrocatalysts by borohydride reduction for alcohol electro-oxidation in alkaline medium
Grantee:Almir Oliveira Neto
Support Opportunities: Regular Research Grants
FAPESP's process: 13/01577-0 - Development of materials and degradation studies of electrocatalysts and supports for alkaline fuel cell
Grantee:Júlio César Martins da Silva
Support Opportunities: Scholarships in Brazil - Post-Doctoral
FAPESP's process: 12/03516-5 - Oxides-C supported electrocatalysts for direct liquid fuel cell anodes
Grantee:Rodrigo Fernando Brambilla de Souza
Support Opportunities: Scholarships in Brazil - Post-Doctoral