Title
Application of AgPt Nanoshells in Direct Methanol Fuel Cells: Experimental and Theoretical Insights of Design Electrocatalysts over Methanol Crossover Effect
Date Issued
01 January 2022
Access level
metadata only access
Resource Type
journal article
Author(s)
Rangel de Melo Rodrigues M.
Machado Ferreira R.
dos Santos Pereira F.
Anchieta e Silva F.
César Azevedo Silva A.
Aguilar Vitorino H.
de Jesus Gomes Varela Júnior J.
Atsushi Tanaka A.
Aurélio Suller Garcia M.
Silva Rodrigues T.
Publisher(s)
John Wiley and Sons Inc
Abstract
Based on theoretical simulations, the best design for obtaining AgPt nanostructures (nanoshells with hollow interior) was unraveled that could exhibit methanol tolerance for oxygen reduction reaction (ORR) that occurs during direct methanol fuel cells (DMFCs) operation. A theoretical investigation of Pt@Ag and Ag@Pt core-shell nanoparticles and AgPt nanoshells′ interaction with oxygen and methanol revealed that the oxygen interaction is significantly more favorable on AgPt nanoshells′ surface, hindering the methanol oxidation reaction (MOR) due to the random arrangement of Ag and Pt atoms. Experimentally, the nanoshells were prepared by a galvanic substitution and immobilized them onto silica, and the material was finely understood by associating electrochemical and physicochemical studies. Cyclic voltammetry showed the reduction and oxidation processes of the catalyst‘s species; however, XPS precisely showed that significant amounts of oxidized species were present (60.5 % of Ag0 and 39.5 % of Ag+, and 55.1 % of Pt0 and 44.9 % of Pt+2), which could affect the performance of the material. Indeed, the catalyst showed an excellent performance to ORR; the system yielded a 4-electron ORR mechanism with just 1.0 wt.% Pt loading, with significant stability after 1000 runs. In addition, Koutecky-Levich and Tafel plots assisted in understanding better the mechanism on the catalyst‘s surface, suggesting a first-electron transfer for the rate-determining step. Also, the catalyst resistance to the methanol crossover, theoretically simulated and predicted, was tested, showing remarkable tolerance for the alcohol up to a concentration of 2 M. Hence, a cathode catalyst with improved selectivity, low metal loading, high stability, and easy preparation was obtained.
Language
English
OCDE Knowledge area
Electroquímica
Subjects
Scopus EID
2-s2.0-85136900324
Source
ChemCatChem
ISSN of the container
18673880
Sponsor(s)
Fundação de Amparo à Pesquisa do Maranhão – FAPEMA (FAPEMA, grant INFRA‐02264/21);
Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq (grant no. 205220/2018–5; 465389/2014–7);
We were able to perform a theoretical investigation on the best AgPt nanostructure configuration to predict an improved system selective to the oxygen reduction in the presence of methanol. We discovered through this initial assessment that AgPt nanoshells presented barrier energy able to produce products selectively of ORR. Experimentally, we employed a galvanic substitution approach to obtain such materials, which were supported in silica to guarantee their good interaction without metal leaching. Up to 2 M methanol concentrations, we attested a selective system, as previously anticipated by the simulations. We compared our catalyst with a commercial Pt/C counterpart and observed kinetic reaction loss, probably due to chosen silica support. However, the slower characteristic of the AgPt/SiO2 was balanced by increasing the methanol crossover effect resistance, allowing us to prove that hollow AgPt nanomaterials can be used for the advance in DMFC technologies. In future studies, we will improve the metal-support interactions with other supports, improving kinetics. Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro – FAPERJ (Grant numbers: E-26/201.431/2021, E-26/211.612/2019, E-26/010.000982/2019) Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq (grant no. 205220/2018–5; 465389/2014–7); Fundação de Amparo à Pesquisa do Maranhão – FAPEMA (FAPEMA, grant INFRA-02264/21); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES, finance Code 001 (grants no.88887.472618/2019-00-PROCAD-AM, 88882.445688/2019-01). Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro – FAPERJ (Grant numbers: E-26/201.431/2021, E-26/211.612/2019, E-26/010.000982/2019) Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq (grant no. 205220/2018–5; 465389/2014–7); Fundação de Amparo à Pesquisa do Maranhão – FAPEMA (FAPEMA, grant INFRA-02264/21); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES, finance Code 001 (grants no.88887.472618/2019-00-PROCAD-AM, 88882.445688/2019-01).
Sources of information:
Directorio de Producción Científica
Scopus