Templated 2D Polymer Heterojunctions for Improved Photocatalytic Hydrogen Production

Area of Science:

• Materials Science
• Photocatalysis
• Organic Chemistry

Background:

• Two-dimensional (2D) polymers are promising organic photocatalysts for solar fuel production.
• Challenges exist in processing 2D polymers and forming heterojunction materials.
• Limited studies explore heterojunctions due to processing difficulties.

Purpose of the Study:

• To develop a novel templating approach for creating 2D polymer heterojunctions.
• To investigate the impact of topological matching on heterojunction performance.
• To evaluate the photocatalytic activity and charge dynamics of the templated materials.

Main Methods:

• A templating strategy was employed to combine imine-based donor and Knoevenagel condensation acceptor polymers.
• Heterojunction formation was analyzed based on topological compatibility.
• Transient absorption spectroscopy was used to study charge separation and extraction dynamics.
• Photocatalytic hydrogen evolution rates were measured with and without hole scavengers.

Main Results:

• Heterojunction formation is highly dependent on the topological match between donor and acceptor polymers.
• The most active templated material showed 3-9 times higher photocatalytic activity than individual components.
• Faster charge separation and more efficient charge extraction were observed in the templated heterojunction.
• High hydrogen evolution rates (>20 mmol h⁻¹ m⁻²) were achieved, even with water and a cobalt redox mediator.

Conclusions:

• The novel templating approach successfully creates highly active 2D polymer heterojunctions.
• Improved charge separation and reduced charge trapping are key to enhanced photocatalytic performance.
• The templated materials show potential for Z-scheme photocatalysis for solar fuel production.