g-C3N4/ZrO2 composite material: A pre-eminent visible light-mediated photocatalyst for rhodamine B degradation in the presence of natural sunlight

Fast charge recombination rate and low visible light response have always been the main restricting factor to the photocatalytic performance of graphitic carbon nitride (g-C3N4). The use of semiconductors to construct com-posites with g-C3N4 has been shown to be an effective way to boost the photocatalytic activity of g-C3N4. In this work, g-C3N4/ZrO2 composite photocatalyst was prepared by simple sonication method using synthesized g-C3N4 and hydrothermally synthesized zirconium oxide (ZrO2) nanoparticles. The photocatalytic activity of as-prepared samples was investigated by Rhodamine B (RhB) degradation under sunlight. The g-C3N4/ZrO2 composites show superior degrading performance than raw g-C3N4 and ZrO2. All pure and composite materials are characterized by XRD, UV-Vis DRS, FT-IR, XPS, SEM, EDX, HR-TEM, BET, PL, and electrochemical measurements to determine the source of the high photoactivity of the g-C3N4/ZrO2 composites. The outcomes of the characterization showed that ZrO2 nanoparticles were evenly dispersed into the layer of g-C3N4. When compared to raw g-C3N4 and ZrO2, the g-C3N4/ZrO2 composites minimize charge transfer resistance and effectively prevent electron-hole recombination. It also has an effect on the band structure and boosts visible-light absorption. Simultaneously, the radical trapping experiments and ESR study exhibited that .O-2(-) and h(+) were the most active species in the catalytic process.