Optimized expanding of interlayer distance for molybdenum disulfide towards enhanced hydrogen evolution reaction

Abstract

Abstract Adjusting the hydrogen-binding free energy (ΔGH*) of two dimensional (2D) MoS2 by changing the interlayer distance has been an effective strategy to improve the intrinsic activity for hydrogen evolution reaction (HER). Herein, a facile solvothermal access via various ratio of N, N-dimethylformamide (DMF)/H2O has been used to modulate interlayer distance of nanostructured MoS2. With increasing of DMF, the interlayer distance of MoS2 can be expanded to 9.4 A with smaller sizes, which may be derived from intercalation effect of DMF. The certain ratio of DMF/H2O (volume ratio of 19/1, MoS2-D19H1) leads to the largest interlayer distances of 10.0 A and the smallest size of nanospheres with less stacking than counterparts synthesized at other ratios of DMF/H2O. The expanded interlayer distance of MoS2-D19H1 may change electronic structure of active sites for HER, implying the improved ΔGH* and the intrinsic activity of MoS2. The smallest size also suggests the more exposure of active sites for HER. The electrochemical measurements demonstrate that MoS2-D19H1 shows the best electrocatalytic performances than MoS2 samples synthesized at other ratio of DMF/H2O. This work may provide a promising strategy to tune the interlayer distance of 2D-layered transition metal dichalcogenide for efficient HER.