Ultra-thin pine tree-like MoS2 nanosheets with maximally exposed active edges terminated at side surfaces on stainless steel fiber felt for hydrogen evolution reaction

Abstract High active edge sites guarantee MoS2 as a promising electrocatalyst alternative for the costly Pt based materials. However, the inherent high surface energy nature of the layer edges thermodynamically blocks the large scale synthesis, and meanwhile poses instability problems. In this work, vertically grown ultra-thin MoS2 nanosheets with a large proportion of exposed edges on commercially available 316L stainless steel fiber felts (SSF) via a simple one-step kinetically controlled hydrothermal process is reported aiming for electrocatalytic H2 production. Notably, the synthesized MoS2 nanosheet presents a three dimensional pine tree-like structure featured by the maximally exposed active edges toward side surfaces. Abundant gaps between the MoS2 nanosheets together with impressive super-hydrophilic property assure the large density of effective edge sites that accessible to electrochemical reaction and the rapid desorption of H2 products, and thus high intrinsic hydrogen evolution reaction (HER) activity. In addition to those electrochemically desired properties, the reliable contact of the MoS2 sheet on the SSF substrate together with the low price, porosity, high conductivity and high chemical corrosion resistance properties of the SSF substrate guarantee the MoS2/SSF electrode as an efficient and durable HER electrode in both strong acidic and alkaline medium for potential commercial applications.