Active Sites-Enriched Hierarchical Weyl Semimetal WTe2 Nanowire Arrays for Highly Efficient Hydrogen Evolution Reaction

Abstract

Weyl semimetal tungsten ditelluride (WTe2), characterized by its high conductivity and robust topological surface state, possesses promising catalytic properties for electrochemical reactions. However, the synthesis of well-defined WTe2 nanostructures has faced challenges, hindering their practical applications. This study introduces a new method for synthesizing Weyl semimetal WTe2 nanowire arrays grown vertically on conductive carbon cloth. Through a selective synthesis process, WTe2 and core–shell semiconductor-semimetal WO3−x–WTe2 nanowires are successfully fabricated via tellurization of WO2.9 nanowires. To gain a comprehensive understanding of the structural, chemical, and catalytic properties of these nanowires, WO2.9 nanowires are gradually converted to WO3−x–WTe2 and WTe2 nanowires. The hierarchical structure of the WTe2 nanowires greatly increases the number of active sites and promotes efficient charge transfer, resulting in exceptional electrochemical catalytic performance. In the hydrogen evolution reaction, WTe2 nanowire arrays exhibit an exceptionally low Tafel slope of 49 mV dec−1, as well as remarkable stability under both high and low current densities. These exceptional properties highlight the potential of WTe2 nanowire arrays as highly effective electrochemical catalysts. It is expected that this facile synthesis approach will pave the way for the fabrication of well-structured Weyl semimetal nanowires, enabling further exploration of their intriguing properties and promising applications.