Interface Modulation of FePc/Porous Ti(HPO4)2 Z-Scheme Heterojunctions with Ultrafine Ag for Efficiently Photocatalytic CO Oxidation

Herein, an integrative Z-scheme heterojunction of ultrafine Ag- (approximate to 4 nm) modulated FePc/porous Ti(HPO4)(2) nanosheet (FePc/Ag/TiP NS) with extended spectrum response is designed and fabricated for efficient CO oxidation. The optimal one exhibits approximately tenfold enhancement in photocatalytic activity compared with the bulky TiP counterpart, even outperforming commercial TiO2 (P25). The greatly improved photoactivity is mainly ascribed to the accelerated Z-scheme charge transfer, and well-defined isolated central metal ion (Fe2+) in FePc with excellent oxygen activation capacity, along with the extended visible light response. The strengthened charge transfer depends on the interfacial modulation of the ultrafine Ag intentionally embedded in the pores of TiP NS, which enables the electrons of TiP NS migration directionally and induces high-dispersion FePc controllable assembly on TiP NS with the increased loading amount. Moreover, it is revealed that CO is previously adsorbed on TiP NS via forming -OH-OC intermediate with the surface hydroxyl and subsequently react with the activated O-2 by the Fe-N-4 sites in FePc to produce CO2 mainly based on in situ diffuse reflectance infrared spectra and near ambient pressure XPS spectra. A new design concept for constructing Ti(HPO4)(2)-based Z-scheme heterojunctions is provided, and the avenues for efficient CO oxidation are paved.

Automated summary

An integrative Z-scheme heterojunction of ultrafine Ag-modulated FePc/porous Ti(HPO4)(2) nanosheet (FePc/Ag/TiP NS) with extended spectrum response is designed for efficient CO oxidation. The enhanced photoactivity is attributed to accelerated Z-scheme charge transfer and the presence of well-defined Fe2+ ion and extended visible light response. The interfacial modulation of ultrafine Ag embedded in TiP NS enables the directional migration of electrons and the controllable assembly of FePc, resulting in strengthened charge transfer. The activated O-2 by Fe-N-4 sites in FePc reacts with CO adsorbed on TiP NS to produce CO2.