Triblock copolymer-assisted synthesis of Z-scheme porous g-C3N4 based photocatalysts with promoted visible-light-driven performance

Abstract

The challenge strategy for construction of the Z-scheme heterostructures including porous g-C3N4 based materials employing triblock copolymer and MCM-41 templates-assisted synthesis is to obtain stable photocatalysts with high charge-separation during photocatalysis application utilizing visible light. In this contribution, synthesis of mesoporous α-Fe2O3, CuO and CoFe2O4 nanoparticles (NPs) on porous g-C3N4 for promoted Hg(II) photoreduction efficiency have been evaluated compared with pristine g-C3N4. A Z-scheme system of mesoporous CuO, CoFe2O4 or Fe2O3-/g-C3N4 heterostructures provides an enhanced photocatalytic Hg(II) reduction, yielding a rate of 628.7, 472.2 and 424.1 μmolg−1h−1, respectively, which is ~7.77, 5.84 and 5.24 times greater than that pristine g-C3N4 (80.85 μmolg−1h−1). The photocatalytic efficiency was improved up ~100, 76.5, and 68.6% over mesoporous CuO, CoFe2O4 and Fe2O3-/g-C3N4, respectively, however, it was 12% over pristine g-C3N4 through 50 min illumination time. The enhanced photoreduction using Z-scheme CuO, CoFe2O4 and Fe2O3-/g-C3N4 heterostructures was attributed to its superb characteristics to expedite the photoreduction of Hg(II), involving: (i) 3D mesostructure and more suitable active sites which improves the Hg(II) adsorption, (ii) high surface area (188 m2 g-1) and narrow bandgap (1.93 eV) and (iii) the superior Z-scheme heterostructures characteristic efficiently enhances the electron-hole pairs separation. This research work creates new windows for mesoporous metal oxides and perovskites/g-C3N4 -based Z-scheme system for wastewater remediation, air purification and clean energy generation.