Hot electron-driven electrocatalytic hydrogen evolution reaction on metal-semiconductor nanodiode electrodes

Area of Science:

• Surface Science
• Electrochemistry
• Materials Science

Background:

• Hot electrons generated on metal catalysts play a crucial role in driving catalytic reactions.
• Understanding and controlling hot electron dynamics is key to developing advanced catalytic processes.

Purpose of the Study:

• To investigate the acceleration of electrocatalytic hydrogen evolution using internally injected hot electrons.
• To explore the potential of hot electron-driven reactions for controlling reactivity at metal-semiconductor interfaces.

Main Methods:

• Fabrication of platinum/silicon (Pt/Si) metal-semiconductor electrodes.
• Application of forward bias voltage to inject hot electrons.
• Electrochemical measurements of the hydrogen evolution reaction (HER) with and without hot electron injection.
• Systematic variation of Pt film thickness to probe hot electron mean free path effects.

Main Results:

• Forward bias injection of hot electrons into Pt/Si electrodes significantly accelerates the hydrogen evolution reaction.
• Observed a positive shift in the onset potential by 160 mV and an 8-fold increase in cathodic current.
• The observed enhancement diminished when Pt film thickness exceeded the hot electron mean free path.

Conclusions:

• Internal injection of hot electrons provides a novel mechanism to enhance electrocatalytic activity.
• This study demonstrates a new pathway for controlling reactivity at liquid-solid interfaces via hot electron dynamics.
• The findings open avenues for designing advanced catalysts and electrochemical devices.