Self-assembly of hollow MoS₂ microflakes by one-pot hydrothermal synthesis for efficient electrocatalytic hydrogen evolution

Highlights: • A new hollow MoS₂ microflakes are prepared by hydrothermal synthesis firstly. • SEM and TEM study show the structural nature of hollow microflakes in depth. • The unique hollow structures have large surface area owing to the cavity. • The hollow microflakes show better HER performance than their solid counterparts. - Abstract: Molybdenum disulfide (MoS₂) has emerged as a promising non-precious metal catalyst for hydrogen evolution reaction (HER) in recent years. Some strategies including nanotechnology as well as atom doping have been employed in the preparing of electrocatalysts for high-activity and stability. To the best of our knowledge, hollow MoS₂ microflakes assembled from ultrathin nanosheets have not been prepared previously. In this work, a simple, facile and environmentally friendly hydrothermal synthesis was utilized for the fabrication of hollow MoS₂ microflakes for the first time. The unique hollow structures have fascinating properties, such as the large surface and low density. The morphology and structure of MoS₂ microflakes were confirmed by XRD, SEM, TEM and Raman. The composition of these materials was identified by the X-ray photoelectron spectroscopy. Notably, the as-prepared hollow MoS₂ microflakes showed better electrocatalytic activity than other samples. The hollow flake-like structure can not only increase the active edge sites owing to the large specific surface area, but also enhance the electron transport to improve the electrocatalytic activity. Benefiting from these factors, the hollow MoS₂ microflakes exhibited electrocatalytic activity and excellent stability with a low overpotential about 85 mV and a Tafel slope of 59 mV per decade.