| Texto completo | |
| Autor(es): Mostrar menos - |
Florindo, Bianca Rocha
;
Hasimoto, Leonardo H.
;
de Freitas, Nicolli
;
Candiotto, Graziani
;
Lima, Erika Nascimento
;
de Lourenco, Claudia
;
de Araujo, Ana B. S.
;
Ospina, Carlos
;
Bettini, Jefferson
;
Leite, Edson R.
;
Lima, Renato S.
;
Fazzio, Adalberto
;
Capaz, Rodrigo B.
;
Santhiago, Murilo
Número total de Autores: 14
|
| Tipo de documento: | Artigo Científico |
| Fonte: | JOURNAL OF MATERIALS CHEMISTRY A; v. 11, n. 37, p. 10-pg., 2023-09-26. |
| Resumo | |
The catalytic sites of MoS2 monolayers towards hydrogen evolution are well known to be vacancies and edge-like defects. However, it is still very challenging to control the position, size, and defective areas on the basal plane of MoS2 monolayers by most of the defect-engineering routes. In this work, the fabrication of etched arrays on ultra-large supported and free-standing MoS2 monolayers using a focused ion beam (FIB) is reported for the first time. By tuning the Ga+ ion dose, it is possible to confine defects near the etched edges or spread them over ultra-large areas on the basal plane. The electrocatalytic activity of the arrays toward the hydrogen evolution reaction (HER) was measured by fabricating microelectrodes using a new method that preserves the catalytic sites. We demonstrate that the overpotential can be decreased up to 290 mV by assessing electrochemical activity only at the basal plane. High-resolution transmission electron microscopy images obtained on FIB patterned freestanding MoS2 monolayers reveal the presence of amorphous regions and X-ray photoelectron spectroscopy indicates sulfur excess in these regions. Density-functional theory calculations enable identification of catalytic defect sites. Our results demonstrate a new rational control of amorphous-crystalline surface boundaries and future insight for defect optimization in MoS2 monolayers. (AU) | |
| Processo FAPESP: | 22/00955-0 - Estudo da influência de deformações mecânicas no desempenho de dispositivos esticáveis baseados em MoS2 para aplicação na área de energia |
| Beneficiário: | Leonardo Hideki Hasimoto |
| Modalidade de apoio: | Bolsas no Brasil - Doutorado |