WCx-Supported RuNi Single Atoms for Electrocatalytic Oxygen Evolution.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Single-atom catalysts (SACs) are crucial for efficient catalysis, but their activity is often limited by strong coordination with support materials.
• Tungsten carbide (WCx) offers a unique support structure for anchoring single atoms with tailored electronic properties.

Purpose of the Study:

• To synthesize and characterize a stable WCx-supported RuNi single-atom catalyst for the oxygen evolution reaction (OER).
• To investigate the structure-activity relationship and understand the mechanism behind the enhanced OER performance.

Main Methods:

• Simple pyrolysis method for catalyst synthesis.
• X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) for structural analysis.
• X-ray photoelectron spectroscopy (XPS) for elemental composition and electronic state determination.
• Electrochemical measurements in 1 m KOH solution to evaluate OER performance.

Main Results:

• Phase-pure WC and W2C with uniformly dispersed atomic RuNi sites were successfully synthesized.
• The WCx-RuNi catalyst exhibited excellent OER activity with a low overpotential of 330 mV at 50 mA/cm2.
• High long-term stability was demonstrated, attributed to the synergistic effect of RuNi atoms and weak interaction with the WCx support.

Conclusions:

• The WCx support facilitates weak bonding of RuNi single atoms, optimizing their electronic structure for OER.
• The synergistic action of Ni addition enhances electron density near the Fermi level, promoting intermediate adsorption and electron transfer.
• This study presents a viable strategy for developing durable and efficient WCx-supported metal SACs for electrochemical applications.