Rational interfacial design of mesoporous g-C₃N₄/CdMoSe quantum dots heterostructures for enhanced photocatalysis

Area of Science:

• Materials Science
• Photocatalysis
• Nanotechnology

Background:

• Semiconductor photocatalysts face challenges with inefficient charge separation and transport.
• Heterostructure interfaces are a promising strategy to enhance photocatalytic performance.
• Graphitic carbon nitride (g-C3N4) based materials are widely studied for photocatalysis.

Purpose of the Study:

• To design and synthesize CdMoSe quantum dots (QDs) decorated mesoporous graphitic carbon nitride (MCN) nanohybrids (CMS-MCN).
• To investigate the interfacial electronic coupling and charge redistribution in the CMS-MCN nanohybrids.
• To evaluate the photocatalytic performance of CMS-MCN for H2O2 and H2 production.

Main Methods:

• Facile construction of CMS-MCN nanohybrids.
• Characterization of electronic structure and band alignment.
• Photocatalytic experiments for H2O2 and H2 production under visible light irradiation.
• Mechanistic studies involving reactive oxygen species detection.

Main Results:

• CMS-MCN nanohybrids exhibited enhanced visible-light absorption and promoted directional charge separation.
• An increased electron density on the MCN surface indicated spontaneous electron migration from CMS QDs to MCN.
• Optimized CMS-MCN achieved a H2O2 production rate of 3945.71 μmol h−1 g−1 and a H2 evolution rate of 14248 µmol h−1 g−1.
• An S-scheme charge-transfer pathway was identified, preserving strong redox potentials.

Conclusions:

• The developed CMS-MCN nanohybrid effectively overcomes the limitations of pristine MCN for photocatalysis.
• Interfacial band-structure engineering is a viable strategy for advancing solar-driven H2O2 and H2 production.
• The synergistic effect of CMS QDs and MCN, coupled with the S-scheme mechanism, leads to significantly enhanced photocatalytic activity.