<p>Two-dimensional transition metal
dichalcogenides (2D TMDCs) have attracted tremendous interest as one prominent
material group promising inexpensive <a>electrocatalysts
for hydrogen evolution reaction (HER)</a>. In the present study, using <a>monolayer MoTe<sub>2</sub> as a representative, we
demonstrated that </a>phase boundaries can provide a viable pathway to activate
the basal plane of 2D TMDCs for enhanced HER performance. Comprehensive
first-principles calculations have been performed to examine the energetics and
structural stabilities of possible 2H/1T’ phase boundary configurations. Three
categories of sites, Te, Mo and hollow sites, have been identified in
energetically stable phase boundaries, as potential catalytic centers for HER,
all indicating enhanced HER activity than the pristine basal lattice. In
particular, the hollow sites, a new group of sites induced by phase boundaries,
show great promise by exhibiting a Gibbs free energy near the thermoneutral value for
hydrogen adsorption, comparable to that of Pt. The mechanisms underlying hydrogen
adsorption at phase boundaries were then revealed, shown to be attributed to
the unique local hydrogen adsorption geometries and electronic structures at
phase boundaries. Our study clarifies the important mechanistic aspects
underlying hydrogen activation at phase boundaries, providing valuable
theoretical insights towards designing new class of
high-performance HER electrocatalysts based on 2D TMDCs.</p>
A Physical Model for Understanding the Activation of MoS
2
Basal‐Plane Sulfur Atoms for the Hydrogen Evolution Reaction
