A polymeric hydrogel electrocatalyst for direct water oxidation

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Metal-free electrocatalysts are crucial for the oxygen evolution reaction (OER).
• Current metal-free OER catalysts predominantly use functionalized conjugated carbon materials, limiting exploration.
• There is a need for novel, efficient, and versatile metal-free OER electrocatalysts.

Purpose of the Study:

• To explore the potential of mesostructured polyacrylate hydrogels as metal-free electrocatalysts for OER.
• To investigate the OER activity, durability, and pH adaptability of these novel hydrogel materials.
• To elucidate the intrinsic active sites and reaction mechanisms of the hydrogel electrocatalysts.

Main Methods:

• Electrochemical characterization of polyacrylate hydrogels for OER performance.
• Theoretical and electrokinetic studies to understand the catalytic mechanism.
• Spectroscopic operando characterizations to identify reaction intermediates.

Main Results:

• The mesostructured polyacrylate hydrogel exhibited exceptional OER activity, comparable to benchmark IrO₂.
• The hydrogel demonstrated high durability and adaptability across various pH environments.
• Positively charged carbon atoms in carboxylate units were identified as intrinsic active sites for OER.
• Superoxide intermediates were detected on the hydrogel backbone during the reaction.

Conclusions:

• Mesostructured polyacrylate hydrogels represent a new class of highly efficient metal-free OER electrocatalysts.
• The study expands the range of carbonaceous materials for OER beyond conjugated systems.
• These polymeric hydrogel electrocatalysts show significant potential for further development and application.