Enhancing High-Salinity Tolerance in Photocatalytic Hydrogen Evolution via Membrane-Integrated Asymmetrically...

Area of Science:

• Materials Science
• Energy Science
• Catalysis

Background:

• Developing efficient photocatalytic hydrogen evolution (PHE) systems for sustainable energy production is crucial.
• High-salinity seawater environments pose significant challenges for existing photocatalyst designs.
• Rational design of core photocatalysts is needed for efficient operation in challenging aquatic conditions.

Purpose of the Study:

• To propose a membrane-integrated collaborative strategy for enhancing photocatalytic hydrogen evolution in high-salinity seawater.
• To investigate the role of asymmetric-polarization photocatalysts modified with specific electron mediators.
• To develop stable and efficient photocatalysts for sustainable hydrogen production from seawater.

Main Methods:

• Modification of graphitic carbon nitride (CN) with asymmetric-polarization electron mediators (TPyB-X) of varying molecular symmetry.
• Fabrication of membrane-integrated photocatalyst systems (CN-A1-EEA).
• Performance evaluation of photocatalytic hydrogen evolution in freshwater and simulated seawater using powder-state and membrane-based catalysts.
• Characterization and theoretical calculations to elucidate the mechanism of enhanced activity.

Main Results:

• Powder-state CN-1%TPyB-A1 achieved a PHE performance of 4179 μmol·g⁻¹·h⁻¹, 6.7 times higher than pure CN.
• The asymmetric structure of TPyB-A1 induced a gradient microelectric field, enhancing charge separation and PHE activity.
• Membrane-based CN-A1-EEA showed stable PHE activity in both freshwater (5114 μmol·m⁻²·h⁻¹) and simulated seawater (5285 μmol·m⁻²·h⁻¹), outperforming powder-state catalysts.

Conclusions:

• The membrane-integrated photocatalyst effectively resists high-salinity environments, offering enhanced stability.
• Asymmetric-polarization photocatalysts are promising for designing efficient hydrogen evolution systems.
• This work provides a new strategy for developing robust photocatalysts for seawater-based sustainable energy applications.