Graphdiyne-WS2 2D-Nanohybrid electrocatalysts for high-performance hydrogen evolution reaction

Layered two-dimension (2D) materials have attracted substantial interest as alternative catalysts for hydrogen evolution reaction (HER). However, there exists a significant challenge in that is the only limited density of active sites concentrated at the layer edges. Herein, for the first time, graphdiyne (GD), a new generation of 2D carbon allotrope developed from the graphene family, is found to be an effective stabilizer and also a reducing agent when it is used to form a layered 2D-nanohybrid (GD-WS2 2D-NH) with WS2 owing to its highly conjugated electronic structure and low reduction potential. Further study shows that the layered GD-WS2 2D-NH synthesized with abundant active edges. Such defect-rich structure with large surface area renders ultrahigh catalytic activity and durability for HER in acidic media. Furthermore, owing to the built-in electric field formed among dissimilar layers (GD and WS2), the enhanced charge transfer leads to high activity of the basal plane sites that were inactive for the HER. As a result, the GD-WS2 2D-NH catalyst presents a reduced HER onset potential as small as 140 mV and a superior Tafel slope as low as 54 mV per decade, making the GD-WS2 2D-NH a promising stable catalyst for the HER reaction. (C) 2017 Elsevier Ltd. All rights reserved.