Size-dependent electrocatalytic hydrogen evolution activity of arrays of edge-like defects in MoS₂ crystals patterned by focused ion beam

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de Lourenco, Claudia ; de Araujo, Ana B. S. ; Hasimoto, Leonardo H. ; Feitosa, Isaque A. A. ; das Neves, Matheus F. F. ; Bettini, Jefferson ; Perfecto, Tarcisio M. ; Rocha, Tulio C. R. ; Mori, Thiago J. A. ; Leite, Edson R. ; Santhiago, Murilo

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF MATERIALS CHEMISTRY A; v. N/A, p. 10-pg., 2024-11-11.

Resumo

Introducing surface defects on molybdenum disulfide (MoS2) crystals plays a crucial role in enhancing the electrocatalytic activity toward the hydrogen evolution reaction (HER). Despite the remarkable progress in this area, the precise control of the size, distance, and defective areas with minimal surface contamination remains unachieved. Conventional microfabrication methods often leave organic residues on the surface that impair electrocatalytic activity and hinder interface elucidation by advanced characterization tools. In this study, we pattern for the first-time arrays of pillars in nanometer-thick MoS2 flakes using a focused ion beam to enhance HER activity. We observe size-dependent stability of the edge-like defects under HER conditions with defective areas. The pillars undergo chemical and structural changes post-patterning due to an amorphization process, unambiguously confirmed by atomic force microscopy, Raman spectroscopy, and synchrotron X-ray photoelectron spectroscopy. Furthermore, the amorphization process is more pronounced in specific in-plane directions, as confirmed by transmission electron microscopy. The electrocatalytic activity of the pillars was measured using a recently reported fabrication method, allowing us to unequivocally correlate defects with HER activity. Microelectrodes with less pillars, i.e. less catalytic sites, demonstrate a lower overpotential of 349 mV at 10 mA cm-2 showcasing a groundbreaking advancement in their fabrication. (AU)

• Processo FAPESP: 23/15689-6 - Avaliação do impacto da inserção de defeitos nas propriedades elétricas e eletroquímicas em monocamadas de MoS2
• Beneficiário: Matheus Felipe Fagundes das Neves
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 22/14720-4 - Dos Átomos às Cerâmicas: Um Estudo de Microscopia Eletrônica de Transmissão sobre o Desenvolvimento de Materiais Transparentes
• Beneficiário: Tarcísio Micheli Perfecto
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• 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
• Processo FAPESP: 23/17576-4 - Geração controlada de defeitos químicos no plano basal do dissulfeto de molibdênio (MoS2)
• Beneficiário: Murilo Santhiago
• Modalidade de apoio: Auxílio à Pesquisa - Regular