Edge Engineering in MoS2 by Chemically Induced Nano-Folding

This study introduces a straightforward technique for edge engineering in MoS2 flakes through chemically induced nano-folding. By utilizing a buffered oxide etchant solution, precise detachment is achieved from the substrate and controlled folding/rolling of MoS2 flakes, resulting in the creation of additional active edges up to 100 times thicker than the original flake. The model material, MoS2 grown on silicon substrates via chemical vapor deposition, undergoes a dramatic transformation in morphology. This transformation is driven by partial detachment from the substrate, followed by bending and folding of the flake boundaries, which generates well-defined additional edges. The impact of edge thickening is demonstrated on fundamental characteristics such as work function, crystallinity, and catalytic properties. Notably, the findings demonstrate that the engineered edges significantly enhance the electrocatalytic activity of MoS2 in hydrogen evolution reactions. This highlights the potential of this method to substantially improve the performance of low-dimensional materials.