Synergistic Effects in Ultrafine Molybdenum-Tungsten Bimetallic Carbide Hollow Carbon Architecture Boost Hydrogen Evolution Catalysis and Lithium-Ion Storage.

Constructing hierarchical heterostructures is considered a useful strategy to regulate surface electronic structure and improve the electrochemical kinetics. Herein, the authors develop a hollow architecture composed of MoC1- x and WC1- x carbide nanoparticles and carbon matrix for boosting electrocatalytic hydrogen evolution and lithium ions storage. The hybridization of ultrafine nanoparticles confined in the N-doped carbon nanosheets provides an appropriate hydrogen adsorption free energy and abundant boundary interfaces for lithium intercalation, leading to the synergistically enhanced composite conductivity. As a proof of concept, the as-prepared catalyst exhibits outstanding and durable electrocatalytic performance with a low overpotential of 103 and 163 mV at 10 mA cm-2 , as well as a Tafel slope of 58 and 90 mV dec-1 in alkaline electrolyte and acid electrolyte, respectively. Moreover, evaluated as an anode for a lithium-ion battery, the as-resulted sample delivers a rate capability of 1032.1 mA h g-1 at 0.1 A g-1 . This electrode indicates superior cyclability with a capability of 679.1 mA h g-1 at 5 A g-1 after 4000 cycles. The present work provides a strategy to design effective and stable bimetallic carbide composites as superior electrocatalysts and electrode materials.