Metallic W/WO₂ solid-acid catalyst boosts hydrogen evolution reaction in alkaline electrolyte.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Alkaline hydrogen evolution reaction (HER) is less active than acidic HER due to proton deficiency.
• Proton transfer is crucial for HER activity, often relying on noble metal catalysts.
• Developing non-noble catalysts for efficient alkaline HER is a significant challenge.

Purpose of the Study:

• To design and investigate an all-non-noble catalyst for efficient alkaline hydrogen evolution reaction.
• To understand the mechanism of proton transfer and active site cycling on the catalyst surface.
• To explore the potential of solid-acid catalysts in alkaline electrolytes.

Main Methods:

• Synthesis of a W/WO2 metallic heterostructure as a solid-acid catalyst.
• Electrochemical characterization including overpotential and Tafel slope measurements.
• In situ and ex situ spectroscopy and first-principle density functional theory (DFT) calculations.

Main Results:

• The W/WO2 catalyst demonstrated excellent HER performance with an ultra-low overpotential (-35 mV at -10 mA/cm2) and a small Tafel slope (-34 mV/dec).
• The catalyst exhibited long-term durability (>50 h) in alkaline electrolyte.
• DFT calculations and spectroscopy revealed a dynamic proton-concentrated surface enabling a fast Volmer-Tafel pathway.

Conclusions:

• The W/WO2 solid-acid catalyst effectively promotes alkaline HER by creating a proton-rich surface.
• This work presents a viable strategy for designing advanced all-non-noble catalysts for efficient hydrogen production.
• The findings offer insights into catalytic mechanisms in alkaline media, potentially guiding future catalyst development.