Layered Transition-Metal Ditellurides in Electrocatalytic Applications-Contrasting Properties

The layered compounds and especially transition-metal dichalcogenides are at the forefront of current research on electrocatalytic materials. Despite the fact that electrocatalytical properties of molybdenum and tungsten disulfides are well-known, their tellurium analogues are significantly less explored. Here we show an effective method for MoTe2 and WTe2 chemical exfoliation based on alkali metal intercalation and subsequent reaction with water. The as-synthesized and exfoliated tellurides were characterized in detail and investigated for potential application in electrocatalysis. The inherent electrochemical activity related to both cation and anion was observed. This is dominantly related to the oxidation tendency of tellurium. The MoTe2 and WTe2 show significantly contrasting properties toward the hydrogen evolution reaction, where MoTe2 shows highly increased HER activity with little dependence on electrochemical treatment, whereas WTe2 shows slightly worse improvement and strong dependence on the electrochemical treatment. In particular, the exfoliated MoTe2 exhibits improved electrocatalytic activity for hydrogen evolution reaction and possesses a huge application potential.