Steer the Rheology of Solvent with Little Surfactant to Exfoliate MoS2 Nanosheet by Liquid Phase Exfoliation Method

Abstract

A surfactant system L64 and alcohol mixture was employed to exfoliate MoS2. To reduce the impact of surfactant on the quality of the nanosheet, the concentration of L64 was decreased to an extremely low value 0.0325 mM. Utilize common ultrasonic bath, the production yield of the nanosheet was increased to about 5% per hour, and statistical results from AFM showed that 40% of the nanosheet were less than 4 nm thick. Rheology characterization showed that surfactant alcohol mixtures were shear thinning fluid, yet the viscosity of L64 system varies directly with the shear rate in the high-speed shear region (higher than 400 s−1), and further affect the shear strength, therefore viscosity at high-speed shear can be considered as an indicator of the effectiveness for the exfoliation system. Exfoliated MoS2 was evaluated by hydrogen evolution reaction, and compared to the bulk MoS2, the 4 wt% Pt/FL-MoS2 improved the overpotential from 366 mV to 273 mV at 10 mA[Formula: see text]cm[Formula: see text]. This study presented a facile and effective route to fabricate 2D MoS2 with much less residue, and bring more opportunities to exploit clean and nontoxic system to exfoliate 2D materials.