High-performance hydrogen evolution electrocatalysis by layer-controlled MoS2 nanosheets

Hydrogen is considered as an important clean energy carrier for the future, and electrocatalytic splitting of water is one of the most efficient technologies for hydrogen production. As a potential alternative to Pt-based catalysts in hydrogen evolution reaction (HER), two-dimensional (2D) molybdenum sulfide (MoS2) nanomaterials have attracted enormous research interest, while the structure control for high-performance HER electrocatalysis remains a considerable challenge due to the lack of efficient preparation techniques. Herein, we reported a one-pot chemical method to directly synthesize 2D MoS2 with controllable layers. Multiple-layer MoS2 (ML-MoS2), few-layer MoS2 (FL-MoS2) and single-layer MoS2 coating on carbon nanotubes (SL-MoS2-CNTs) can be efficiently prepared through the modulation of experimental conditions. The enhanced catalytic activity in HER is demonstrated by reducing the layer number of MoS2 nanosheets. Remarkably, the optimized SL-MoS2-CNTs sample showed long-term durabilitywith an accelerated degradation experiment even after more than 10 000 recycles, and high HER activity with an onset over-potential of only similar to 40 mV vs. RHE. This study introduces a novel, cheap and facile strategy to prepare layer-controlled 2D MoS2 nanosheets in a large quantity, and is expected to broaden the already wide range energy applications of 2D MoS2 nanosheets.