Monolayer MoS₂ quantum dots as catalysts for efficient hydrogen evolution

Abstract

A multi-exfoliation route was used to prepare monolayer MoS2 quantum dots with improved electrocatalytic activity for hydrogen evolution.

Hydrogen evolution activity of individual mono-, bi-, and few-layer MoS 2 towards photocatalysis

“…These numbers are in good agreement with reported values for 1L MoS 2 by Voiry et al [65], but high compared to other reports in literature with TOFs of about 10-100 s −1 [4,69]. Overall, the TOF increases for more negative overpotentials as expected, and the determined TOF at 0 V is in the range of about 1 s −1 , again in good agreement with literature values for thin MoS 2 layers [68].…”

“…At 0.3 V, the TOFs reach approximately 4 · 10 3 s −1 , 1 · 10 4 s −1 , and 2 · 10 4 s −1 for bulk, 2L and 1L MoS 2 -flakes, respectively. These values are in excellent agreement with the reported values for monolayer MoS 2 by Voiry et al [65], but rather high compared to other reports in literature with deduced TOFs of about 10-100 s −1 [4,69].…”

Molybdenum disulfide quantum dots: synthesis and applications

“…The peak spacing for MoS 2 QDs (22.5 cm -1 ) was less than that of bulk MoS 2 (25.7 cm -1 ) revealing the monolayer structure of MoS 2 QDs. [37] It was also observed that, the intensity of A 1g mode decreases with increase in times of exfoliation due to the decrease in layer-layer interactions. [54] …”

“…Also, Qiao et al [37] have reported the monolayer MoS 2 QDs with enhanced HER catalytic activity having lower onset over potential of about 120 mV and a small Tafel slope of 69 mV dec -1 . Various catalysts such as, MoS 2 nanosheets (NSs), MoS 2 nanoflowers (NFs), MoS 2 QD with their composites MoS 2 NSs/RGO, MoS 2 NFs/RGO and MoS 2 QD/RGO were synthesized by the facile sonication method.…”

“…[35] MoS 2 QDs convince both large edge-to-volume ratio and high in-plane electron transport mutually when compared to other MoS 2 nanostructures. [36] The MoS 2 QDs have been scrutinized for their remarkable size dependent optical and electronic properties that caused a great sensation in numerous applications including HER, [37] bio-imaging, [38,39] sensors, [40] photodetectors, [41] and photocatalyst. [42] Because of the quantum confinement effect, there is an increase in the band gap of the MoS 2 QDs.…”