Electrochemically chopped WS2 quantum dots as an efficient and stable electrocatalyst for water reduction

Abstract

Advancements in the search for efficient H₂ evolving electrocatalysts by engineering the structure and electronic properties of bulk materials at the nano regime have had a constructive impact on realizing better performance with ultralow catalyst loading. In this work, we investigate the electrochemical hydrogen evolution catalysis of WS₂ quantum dots (QDs) synthesized electrochemically. WS₂ QDs were evaluated for a hydrogen evolution reaction (HER) in 0.5 M H₂SO₄ as a binder-less electrocatalyst, which necessitated a low HER onset of 190 mV and reached −200 mA cm⁻² at 473 mV. In contrast, the bulk WS₂ exhibited a poor performance, which required 780 mV to drive −50 mA cm⁻². The electrochemical disintegration of bulk WS₂ into QDs is the key behind such activation.