MAX Phase (Nb₄AlC₃) For Electrocatalysis Applications

Autor(es)

Gandara, Meriene ; Mladenovic, Dusan ; Martins, Marta de Jesus Oliveira ; Rakocevic, Lazar ; de Assis, Joao Marcos Kruszynski ; Sljukic, Biljana ; Goncalves, Emerson Sarmento

• Tipo de documento: Artigo Científico
• Fonte: SMALL; v. 20, n. 29, p. 15-pg., 2024-02-25.

Resumo

In search for novel materials to replace noble metal-based electrocatalysts in electrochemical energy conversion and storage devices, special attention is given to a distinct class of materials, MAX phase that combines advantages of ceramic and metallic properties. Herein, Nb4AlC3 MAX phase is prepared by a solid-state mixing reaction and characterized morphologically and structurally by transmission and scanning electron microscopy with energy-dispersive X-ray spectroscopy, nitrogen-sorption, X-ray diffraction analysis, X-ray photoelectron and Raman spectroscopy. Electrochemical performance of Nb4AlC3 in terms of capacitance as well as for oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) is evaluated in different electrolytes. The specific capacitance Cs of 66.4, 55.0, and 46.0 F g(-1) at 5 mV s(-1) is determined for acidic, neutral and alkaline medium, respectively. Continuous cycling reveals high capacitance retention in three electrolyte media; moreover, increase of capacitance is observed in acidic and neutral media. The electrochemical impedance spectroscopy showed a low charge transfer resistance of 64.76 omega cm(2) that resulted in better performance for HER in acidic medium (Tafel slope of 60 mV dec(-1)). In alkaline media, the charge storage value in the double layer is 360 mF cm(-2 )(0.7 V versus reversible hydrogen electrode) and the best ORR performance of the Nb4AlC3 is achieved in this medium (Tafel slope of 126 mV dec(-1)). (AU)

• Processo FAPESP: 22/02737-0 - Desenvolvimento de dispositivos supercapacitores a partir de eletrodos de nanomateriais 2D e 3D: grafeno, MXenos e nanoóxidos metálicos
• Beneficiário: Emerson Sarmento Gonçalves
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 22/02347-7 - Novas tecnologias para supercapacitores e baterias de íon lítio a partir de MXenos dopados com terras raras
• Beneficiário: Meriene Gandara
• Modalidade de apoio: Bolsas no Brasil - Doutorado