Effect of Intrinsic Ferroelectric Phase Transition on Hydrogen Evolution Electrocatalysis

Area of Science:

• Materials Science
• Electrochemistry
• Condensed Matter Physics

Background:

• Heterogeneous electrocatalysis relies on material electronic structures.
• Ferroelectric-to-paraelectric phase transitions alter electron states, potentially affecting electrocatalytic activity.
• The correlation between ferroelectricity and electrocatalysis remains largely unexplored.

Purpose of the Study:

• To investigate the impact of ferroelectric-to-paraelectric phase transition on intrinsic electrocatalytic activity.
• To explore the ferroelectro-catalytic effect on the hydrogen evolution reaction (HER) using two-dimensional ferroelectric CuInP2S6.
• To understand how modifying the electronic structure through phase transition influences catalytic thermodynamics and kinetics.

Main Methods:

• Experimental investigation of hydrogen evolution reaction catalysis over CuInP2S6.
• Theoretical calculations to elucidate the underlying mechanisms.
• Analysis of overpotential and apparent activation energy changes during the phase transition.
• Characterization of catalytic activity on ferroelectric and paraelectric phases of CuInP2S6 with Pt single-atom loading.

Main Results:

• Observed discontinuity in overpotential and apparent activation energy for CuInP2S6 during ferroelectric-to-paraelectric phase transition at 318 K.
• Demonstrated a ferroelectro-catalytic effect influencing HER thermodynamics and kinetics.
• Pt single-atom loaded CuInP2S6 in the paraelectric phase exhibited enhanced HER activity with lower apparent activation energy compared to the ferroelectric phase.

Conclusions:

• The ferroelectric-to-paraelectric phase transition significantly regulates intrinsic electrocatalytic activity.
• Copper hopping between sulfur planes in CuInP2S6 leads to alternating strong and weak H adsorption at Pt sites, optimizing HER.
• This work establishes a new strategy for designing advanced electrocatalysts by leveraging ferroelectric phase transitions.