Fermi level induced band edge alignment and band bending in Ag3PO4/Cu2O p-n heterojunction for proficient photocatalytic applications

Abstract

Fabrication of binary p-n heterojunction and the band alignment at the interface of the individual semiconductor photocatalyst has been extensively studied to verify superior charge separation and migration capability in photocatalytic applications. Here, a simple wet chemical followed by a hydrothermal fabrication strategy was introduced for the development of the binary p-n Ag3PO4/Cu2O heterostructures. The tunable band structure of individual semiconductors with the work function (φ), witnessed a band bending at the space charge region. The bending at the interface induces a carrier concentration gradient and manifests a rectifying current transport diode. The fabricated p-n heterostructures and carrier migration between n-type Ag3PO4 and p-type Cu2O were verified by different morphological and physicochemical methods. The band banding at the interface, leading to a narrow depletion region, favors the tunneling of electron-hole pairs through a Z-scheme carrier transport mechanism. The electron-hole pair movement has further been confirmed by considering the band edge position after contact, photocatalytic scavengers, and the radical trapping experiment. The Ag3PO4/Cu2O p-n heterojunction photocatalyst manifested a 737.4 μmol g−1h−1 of H2 generation and 91% endosulfan degradation efficiency, these are 12 and 9 times higher than that of pure Ag3PO4. The p-n heterojunction photocatalyst displayed a higher current density with electron-hole migration efficiency, synergistically enhancing the catalytic activity through the interfacial space charge junction.