resumo
Mesoporous Co(3)O(4)mixed CoO onto reduced graphene oxide (rGO) nanocomposites were obtained by an easy surfactant-free synthesis using urea as hydrolyzing agent. This route enabled nanomaterials presenting tuned morphology, surface composition and oxide-rGO interactions as revealed by the different characterization techniques. Indeed, nanostructures varied from broom-like, chrysanthemum-like to micro-sized sheet-like morphologies. The amount of Co(3)O(4)phase was shown to be gradually rising as the urea amount increases being always higher at the surface than in the bulk. Different oxide-rGO interactions have also been demonstrated, suggesting that high amounts of urea cause a decrease in the size of the nanoparticles and limit their superposition. The catalysts prepared at high urea concentrations showed more exposed electroactive surface and enhanced activity as bifunctional oxygen electrocatalysts. Furthermore, the most active nanocomposite exhibited remarkable stability, making it a very promising candidate for the elaboration of a stable and truly reversible air electrode in alkaline media.
palavras-chave
GRAPHENE OXIDE; RAMAN-SPECTRA; EVOLUTION REACTION; COBALT OXIDE; REDUCTION; METAL; HYBRID; CATALYSTS; SPECTROSCOPY; FILMS
categoria
Electrochemistry; Materials Science
autores
Abidat, I; Ferreira, P; Napporn, TW; Rousseau, J; Guignard, N; Canaff, C; Morais, C; Habrioux, A; Kokoh, KB
nossos autores
Paula Celeste da Silva Ferreira
Investigador CoordenadorProjectos
CICECO - Aveiro Institute of Materials (UID/CTM/50011/2019)
Projeto de Investigação Exploratória: Paula Ferreira (IF_Paula Ferreira)
agradecimentos
This work was supported by the Agence Nationale de la Recherche (ANR), project E Air (ANR-14-CE05-0036-01). IA is grateful for this financial support (PhD grant). This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, FCT Ref. UID/CTM/50011/2019, financed by national funds through the FCT/MCTES. PF thanks FCT for the grant IF/00300/2015.