Atomically thin photoanode of InSe/graphene heterostructure

Area of Science:

• Materials Science
• Electrochemistry
• Photocatalysis

Background:

• Efficient photoelectrochemical water splitting is crucial for sustainable energy production.
• Understanding ion kinetics at the photoelectrode surface is key to improving device efficiency.
• Macroscopic electrodes hinder the isolation of surface effects from bulk properties.

Purpose of the Study:

• To investigate the potential of atomically thin two-dimensional (2D) materials for photoelectrochemical water splitting.
• To explore the role of ion kinetics and charge recombination in photocurrent generation.
• To develop a stable and highly efficient photoanode for water splitting.

Main Methods:

• Fabrication of a graphene-encapsulated InSe monolayer photoanode.
• Characterization of the photoanode's performance in photoelectrochemical water splitting.
• Analysis of photocurrent density and its dependence on applied potential.
• Investigation of ion-surface interactions and charge recombination dynamics.

Main Results:

• Achieved a photocurrent density exceeding 10 mA cm^-2 at 1.23 V vs. reversible hydrogen electrode, significantly higher than other 2D materials.
• Observed a persistent photocurrent after illumination cessation, indicating suppressed electron-hole recombination and trapped holes.
• Demonstrated strong coupling between hydroxide ions and photo-generated holes at the InSe surface.

Conclusions:

• Atomically thin InSe is a promising material for high-efficiency photoelectrochemical water splitting.
• The unique properties of 2D materials enable detailed studies of surface ion kinetics.
• This work provides a platform for designing next-generation photoelectrodes for solar fuel generation.