Tungsten-Assisted Phase Tuning of Molybdenum Carbide for Efficient Electrocatalytic Hydrogen Evolution

Abstract

Phase tuning during crystal phase transformation is an important but challenging step toward the development of effective hydrogen evolution reaction (HER) catalysts. Herein, we report on a feasible approach to achieve effective polycrystalline molybdenum carbides during transformation from α-phase to β-phase through the regulation of additive (tungsten) amount. Benefiting from the optimal Mo-C bond lengths and abundant active sites, molybdenum carbide prepared with a moderate addition of tungsten enhanced electrocatalytic activity and stability compared with pure α-phase and β-phase MoC in the HER, and only required an overpotential of 148 and 93 mV to drive 20 mA cm of current density in 0.5 M HSO and 1.0 M KOH, respectively.

Disordering the Atomic Structure of Co(II) Oxide via B‐Doping: An Efficient Oxygen Vacancy Introduction Approach for High Oxygen Evolution Reaction Electrocatalysts

“…Electrochemical water splitting is widely considered to be a critical step for efficient renewable energy conversion via the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) . Nevertheless, the OER, which involves four proton‐couple electron transfer steps, has a high activation barrier due to the sluggish reaction kinetics .…”

Interface engineering in transition metal carbides for electrocatalytic hydrogen generation and nitrogen fixation

“…27 Furthermore, during the carbide synthesis process, the generation of surface contaminants blocks the active sites and cavities, resulting in the degradation of electrocatalytic activities. 28 In general, carbides are typically prepared by solid-solid or gas-solid reactions to achieve high surface area, namely, direct pyrolysis of metal carbonyl compounds, or reaction of metal/metal oxides with a C source. 22 Consequently, the aggregation and/or excessive growth of TMCs during pyrolysis at relatively high temperatures leads to a reduction in the active sites and electrocatalytic activities for electrochemical reactions.…”

Stoichiometry and surface structure dependence of hydrogen evolution reaction activity and stability of MoxC MXenes

“…Molybdenum carbide is one of the most widely studied transition metal carbide based catalysts for HER 9,[12][13][14][15] . Vrubel et al showed that the activity of bulk Mo2C is relatively independent of pH, with overpotentials at 10 mA/cm 2 , η, at pH 0 and 14 of 209 mV and 191 mV 9 , respectively.…”