Search

[Display omitted] • A novel g-C 3 N 4 /Fe 2 O 3 /rGO ternary composite was synthesised using a hydrothermal process. • The catalyst exhibits a high photocatalytic oxidation efficiency for the removal of sulfamethoxazole. • Reactive oxygen species were identified by quenching tests and electron paramagnetic resonance spectra. • Detailed mechanistic studies were performed to deduce the radical and non-radical degradation pathways. Rational design of semiconductor photocatalysts is an effective way to achieve efficient visible-light-driven environmental remediation. Herein, a series of graphitic carbon nitride (g-C 3 N 4) engineered hematite (Fe 2 O 3)/reduced graphene oxide (rGO) photocatalysts were synthesised and employed in visible-light-driven photo-Fenton-like degradation of sulfamethoxazole (SMX). The exceptional performance of the optimal photocatalyst (0.4-FerGCN-3) was achieved because of the successful structural integration of g-C 3 N 4 /Fe 2 O 3 /rGO for efficient separation and migration of photoinduced charge carriers (e−/h+). Photochemical decomposition efficiency was also optimised by analysing the important reaction parameters such as initial catalyst loading, initial H 2 O 2 dosage, pH, and reaction temperature. Detailed studies on the generation of reactive species and degradation intermediates were performed to propose a possible mechanism for SMX degradation. The findings may provide not only a strategy for nanostructure engineering of semiconductor photocatalysts but also insights into the effective remediation of emerging contaminants such as SMX. [ABSTRACT FROM AUTHOR]

[Display omitted] • Single atom Cu in the configuration of Cu-N 3 was anchored on hollow spherical g-C 3 N 4 to form SACu- hs CN. • The acetaminophen degradation activity of SACu- hs CN was superior to the sample of AGCu- hs CN with aggregated Cu particles via H 2 O 2 activation. • The SACu- hs CN/H 2 O 2 system degraded acetaminophen with a good durability. • 1O 2 unusually played a dominant role in degradation rather than the common OH radicals. Discharge of recalcitrant pharmaceuticals into aquatic systems has caused severe impacts on public health and ecosystem. Advanced oxidation processes (AOPs) are effective for eliminating these refractory pollutants, for which single-atom catalysts (SACs) become the state-of-the-art materials owing to the maximized exposure of active metal sites. In this work, hollow spherical graphitic carbon nitride (hs CN) was fabricated to incorporate copper species to develop Fenton-like catalysts for acetaminophen (ACT) removal. Through pyrolysis of supramolecular assemblies derived from melamine-Cu complex and cyanuric acid, single atom Cu-N 3 sites were anchored on hs CN by N-coordination to obtain SACu- hs CN. In virtue of the atomically dispersed Cu-N 3 sites as well as the hollow structure of hs CN providing smooth channels for the interactions between single Cu atoms and reactants, the optimal 5.5SACu- hs CN removed 94.8% of ACT after 180 min of Fenton-like reactions, which was superior to that of 5.5AGCu- hs CN with aggregated Cu particles on hs CN (56.7% in 180 min). Moreover, 5.5SACu- hs CN was still active after four cycles of regeneration. The mechanism investigation demonstrated that both hydroxyl radicals (OH) and singlet oxygen (1O 2) contributed to ACT degradation in 5.5SACu- hs CN/H 2 O 2 system, in which non-radical 1O 2 played the dominant role. [ABSTRACT FROM AUTHOR]