Converting Ag3PO4/CdS/Fe doped C3N4 based dual Z-scheme photocatalyst into photo- Fenton system for efficient photocatalytic phenol removal

Abstract

In this work, a dual Z-scheme Ag3PO4/CdS/Fe-g-C3N4 (AP/CdS/FeCN) photocatalyst was prepared by precipitation- deposition method. AP/CdS/FeCN photocatalyst was converted into the heterogenous photo-Fenton system with the addition of H2O2. The synergistic coupling between AP/CdS/FeCN and H2O2 resulted in enhanced for phenol degradation, with a rate constant of constant 6.2 × 10−4 s-1, which is 1.31 and 1.61 times than that of AP/CdS/FeCN and Fe2O3/H2O2. The enhancement in photodegradation was attributed to (i) more regeneration of Fe2+ ions, (ii) enhanced visible light absorption, (iii) elevated redox potential due to more hydroxyl radical's formation, and (iv) low Fe leaching in the reaction solution. As indicated by EIS, PL, and trapping experiments, photoinduced CB electrons of g-C3N4 and CdS were transferred entirely to Fe3+ to regenerate Fe2+ ions to accelerate the Fenton cycle. In comparison to the conventional Fe2O3/H2O2 Fenton process, Fe ion leaching in AP/CdS/FeCN/H2O2 catalytic system was almost negligible. It confirmed strong chemical interaction of Fe3+ with g-C3N4. AP/CdS/FeCN/H2O2 displayed significant catalytic efficacy and firmness for five successive catalytic cycles. Moreover, the AP/CdS/FeCN/H2O2 nanocomposite exhibited substantial mineralization perfomance for other phenolic pollutants. The results demonstrate that AP/CdS/FeCN/H2O2 catalytic system has the potential for water purification.