Active Sites‐Enriched Hierarchical Weyl Semimetal WTe ₂ Nanowire Arrays for Highly Efficient Hydrogen Evolution Reaction

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 WO_3- _x-WTe₂ nanowires are successfully fabricated via tellurization of WO_2.9 nanowires. To gain a comprehensive understanding of the structural, chemical, and catalytic properties of these nanowires, WO_2.9 nanowires are gradually converted to WO_3- _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.