Hybridization of Bimetallic Molybdenum‐Tungsten Carbide with Nitrogen‐Doped Carbon: A Rational Design of Super Active Porous Composite Nanowires with Tailored Electronic Structure for Boosting Hydrogen Evolution Catalysis

• Published in: Advanced functional materials Vol. 30; no. 40
• Main Authors: Li, Huan, Hu, Minghao, Zhang, Luyao, Huo, Lili, Jing, Peng, Liu, Baocang, Gao, Rui, Zhang, Jun, Liu, Bin
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.10.2020
• Subjects: Accessibility; bimetallic carbides; Bimetals; Carbon; Catalysis; Chemical composition; Cloth; composite nanowires; Composite structures; electrocatalysis; Electrocatalysts; Electrodes; Electronic structure; Free energy; Hydrogen; hydrogen evolution reaction; Hydrogen evolution reactions; Hydrogen-based energy; Materials science; Molybdenum; Nanowires; Nitrogen; nitrogen‐doped carbon; Porosity; Tungsten carbide
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202003198

An ecofriendly and robust strategy is developed to construct a self‐supported monolithic electrode composed of N‐doped carbon hybridized with bimetallic molybdenum‐tungsten carbide (MoxW2−xC) to form composite nanowires for hydrogen evolution reaction (HER). The hybridization of MoxW2−xC with N‐doped carbon enables effective regulation of the electrocatalytic performance of the composite nanowires, endowing abundant accessible active sites derived from N‐doping and MoxW2−xC incorporation, outstanding conductivity resulting from the N‐doped carbon matrix, and appropriate positioning of the d‐band center with a thermodynamically favorable hydrogen adsorption free energy (ΔGH*) for efficient hydrogen evolution catalysis, which forms a binder‐free 3D self‐supported monolithic electrode with accessible nanopores, desirable chemical compositions and stable composite structure. By modulating the Mo/W ratio, the optimal Mo1.33W0.67C @ NC nanowires on carbon cloth achieve a low overpotential (at a geometric current density of 10 mA cm−2) of 115 and 108 mV and a small Tafel slope of 58.5 and 55.4 mV dec−1 in acidic and alkaline environments, respectively, which can maintain 40 h of stable performance, outperforming most of the reported metal‐carbide‐based HER electrocatalysts. A 3D self‐supported monolithic electrode (MoxW2−xC@ NC/CC) made from bimetallic molybdenum‐tungsten carbide (MoxW2−xC) embedded in N‐doped carbon (NC) to form composite nanowires on carbon cloth (CC) is fabricated for the hydrogen evolution reaction. The ultrafine MoxW2−xC nanoparticles are effective in regulating the electronic structure of N‐doped carbon layers to achieve the optimized hydrogen adsorption/desorption for efficient hydrogen evolution.