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

Developing efficient photocatalytic hydrogen evolution (PHE) systems under a high-salinity seawater environment is extremely attractive for sustainable energy, which still suffers from the rational design of core photocatalysts. Here, a membrane-integrated collaborative strategy via incorporating asymmetric-polarization photocatalysts was proposed. The specific electron mediators (TPyB-X) bearing diverse molecular symmetry were used to modify the prototypical semiconductor graphitic carbon nitride (CN). Among them, powder-state CN-1%TPyB-A1 exhibits the best PHE performance of 4179 μmol·g^-1·h^-1, which is 6.7 times over pure CN. Characterization and theoretical calculations reveal that the asymmetric structure of TPyB-A1 facilitates the formation of a gradient microelectric field, which promotes directional charge separation and contributes to the enhanced PHE activity. Moreover, the membrane-based CN-A1-EEA displays a satisfactory PHE activity with both freshwater (5114 μmol·m^-2·h^-1) and simulated seawater (5285 μmol·m^-2·h^-1), exhibiting more stable performance than the powder-state CN-1%TPyB-A1 (decreasing by 34%). This work demonstrates that the membrane-integrated photocatalyst can effectively resist high-salinity environments, which gives a new clue to rationally design the related materials working in seawater.