Pt Edge-Doped MoS2 : Activating the Active Sites for Maximized Hydrogen Evolution Reaction Performance.

The demand of clean energy calls for efficient and low-cost hydrogen evolution reaction electrocatalysts. Fabricating hybrid catalysts from noble/non-noble catalysts is a practical route to reducing the consumption of noble metals and enhancing catalytic efficiency. Here, 2H-MoS2 is etched and edge-doped with Pt nanoparticles using focused ion beam and photoreduction techniques. Precise comparison of as-prepared samples demonstrates that the enhancement of catalytic performance can be controlled through tuning the catalyst defect length. On this basis, remarkably high performance is obtained by designing a specific defect array that is superior to commercial Pt/C with less Pt loading and higher mass activity. It has been proved by experimentation and COMSOL Multiphysics simulations that the promotion of catalytic activity not only benefits from the synergistic effect of Pt and edge active sites, but also contributes to the increased potential at the edges of the designed defect. This study sheds light on the mechanism of understanding nanoscale edge-doped hybrid catalysts and provides a feasible strategy for the full utilization of noble metals.