Invited paperExcellent performance of ordered Ag-g-C3N4/SBA-15 for photocatalytic ozonation of oxalic acid under simulated solar light irradiation

- Ordered Ag-g-C3N4/SBA-15 was successfully synthesized using SBA-15 as support.
- 4% Ag-g-C3N4/SBA-15 shows efficient capability for photocatalytic ozonation of OA.
- The stability and mechanism in photocatalytic ozonation process are investigated.

Ordered Ag-g-C3N4/SBA-15 was successfully synthesized using SBA-15 as a template and support. The samples were characterized by TEM, XRD, XPS, N2 adsorption-desorption. The results showed that metallic silvers with diameter 15 nm were distributed on the surface of g-C3N4 thin-layered. The specific surface area of the composite was 563.4 m2 g−1. As the final products for ozonation, oxalic acid was used to investigate its catalytic ability in heterogeneous photocatalytic ozonation under simulated solar light irradiation. Ordered Ag-g-C3N4/SBA-15 with the mass ratio of silver nitrate/dicyandiamide around 4% was found to be the most efficient for oxalic acid degradation. The kinetic constant was 1.60 and 2.52 times as high as that of solar light/Ag-g-C3N4/O3 and solar light/g-C3N4/O3 process, respectively. It demonstrated that both the Ag nanoparticles and improved specific surface area contributed to the enhancement, which promoted the decomposition of O3 and increased the active sites in reaction. The synergy index for photocatalytic ozonation of oxalic acid was calculated to be 5.71, which indicated a superior synergistic effect between photocatalysis and ozonation. In addition, 4% Ag-g-C3N4/SBA-15 samples showed good stability in photocatalytic ozonation process by cycled for four times, and the mechanism was also confirmed in this study. It is suggested that Ag-g-C3N4/SBA-15 composites is a promising catalyst for the practical application of photocatalytic ozonation.

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