@article{D3TA04225Ab,
title = {Patterning edge-like defects and tuning defective areas on the basal plane of ultra-large MoS2 monolayers toward hydrogen evolution reaction},
author = {Bianca Rocha Florindo and Leonardo Hideki Hasimoto and Nicolli Freitas and Graziâni Candiotto and Erika Nascimento Lima and Cláudia Lourenço and Ana Beatriz Sorana Araujo and Carlos Ospina and Jefferson Bettini and Edson Roberto Leite and Renato S Lima and Adalberto Fazzio and Rodrigo B. Capaz and Murilo Santhiago},
url = {http://dx.doi.org/10.1039/D3TA04225A},
doi = {10.1039/D3TA04225A},
year = {2023},
date = {2023-01-01},
urldate = {2023-01-01},
journal = {J. Mater. Chem. A},
pages = {-},
publisher = {The Royal Society of Chemistry},
abstract = {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 propagation of defects on the basal plane of MoS2 monolayers by most of defect-engineering routes. In this work, the fabrication of etched arrays on ultra-large supported and free-standing MoS2 monolayers using 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 propagate them over ultra-large areas on the basal plane. The electrocatalytic activity of the arrays toward 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 provide 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.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
