Charge Controlled Engineering: Constructing Built-in Electric Fields at CoCu-ZIF/Cu3P-GDY Interfaces for Enhanced Photocatalytic Hydrogen Evolution

Abstract

Rational design of interfacial electric fields in nanostructures for accelerated photogenerated carrier transfer and separation. First, Cu⁺-mediated self-assembly engineering narrows the bandgap of ZIF-67 while extending the light absorption range of CoCu-ZIF. Furthermore, hierarchical architecture is constructed to incorporate the cocatalyst Cu₃P-GDY. The staggered energy levels in the resulting CoCu-ZIF/Cu₃P-GDY composite generate a strong driving force. Comprehensive characterization, including density functional theory calculations and Mott–Schottky analysis, confirm the formation of an S-scheme heterojunction between GDY and CoCu-ZIF. Cu₃P acts as an electron bridge to promote the directional transfer of photogenerated carriers driven by interfacial electric fields. Differential surface photovoltage signals demonstrate that the robust interfacial electric field enables efficient carrier separation in the CoCu-ZIF/Cu₃P-GDY composite. This work establishes a new paradigm for enhancing catalytic performance through broadened light absorption and rationally engineered interfacial electric fields.