Layered Nano‐Mosaic of Niobium Disulfide Heterostructures by Direct Sulfidation of Niobium Carbide MXenes for Hydrogen Evolution
Samantha Husmann, Mohammad Torkamanzadeh, Kun Liang, Ahmad Majed, Chaochao Dun, Jeffrey J. Urban, Michael Naguib, Volker Presser
Abstract
Abstract MXene‐transition metal dichalcogenide (TMD) heterostructures are synthesized through a one‐step heat treatment of Nb 2 C and Nb 4 C 3 . These MXenes are used without delamination or any pre‐treatment. Heat treatments accomplish the sacrificial transformation of these MXenes into TMD (NbS 2 ) at 700 and 900 °C under H 2 S. This work investigates, for the first time, the role of starting MXene phase in the derivative morphology. It is shown that while treatment of Nb 2 C at 700 °C leads to the formation of pillar‐like structures on the parent MXene, Nb 4 C 3 produces nano‐mosaic layered NbS 2 . At 900 °C, both MXene phases, of the same transition metal, fully convert into nano‐mosaic layered NbS 2 preserving the parent MXene's layered morphology. When tested as electrodes for hydrogen evolution reaction, Nb 4 C 3 ‐derived hybrids show better performance than Nb 2 C derivatives. The Nb 4 C 3 ‐derived heterostructure exhibits a low overpotential of 198 mV at 10 mA cm −2 and a Tafel slope of 122 mV dec −1 , with good cycling stability in an acidic electrolyte.