Manipulating the interfacial water structure by electron redistribution for the hydrogen evolution reaction.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Sluggish water dissociation in alkaline electrolytes limits hydrogen evolution reaction (HER) kinetics, especially on Ru-based catalysts.
• Water molecule configuration at the catalyst interface is crucial but difficult to control due to random distribution.

Purpose of the Study:

• To investigate how catalyst electron distribution affects water adsorption and orientation.
• To develop an efficient catalyst for the hydrogen evolution reaction (HER) in alkaline media.

Main Methods:

• Fabrication of a NiRu alloy supported on nitrogen-doped carbon (NiRu/NC) as a model catalyst.
• Analysis of electron distribution and charge transfer within the NiRu alloy.
• In situ Raman spectroscopy to confirm water molecule configuration.

Main Results:

• Ni introduction induced charge transfer from Ni to Ru, strengthening local electric fields.
• Electron-rich Ru sites attracted K⁺ cations, promoting K⁺ cation-hydrated water molecules in an H-down configuration.
• NiRu/NC demonstrated excellent HER performance with low overpotentials (16 mV at 10 mA cm^-2 and 344 mV at 1000 mA cm^-2).

Conclusions:

• Catalyst-induced manipulation of water molecule orientation is an effective strategy to enhance HER kinetics.
• The NiRu/NC catalyst shows significant potential for efficient hydrogen production in alkaline electrolytes.