Bifunctional Purposes of Composite TiO2/CuO/Carbon Dots (CDs): Faster Photodegradation Pesticide Wastewater and High Performance Electromagnetic Wave Absorber

The multifunction material for EMI absorber and photocatalytic of composite TiO2/CuO/Carbon Dots (CDs) by S-scheme has been successfully fabricated composite by the solid-state method as a green photocatalyst. In this work, the CDs were synthesized from Senna Siamea seeds by solid-state method for various calcination temper- atures: 250°C, 275°C, and 300°C. The CDs is used to help electron/hole charge in the photocatalysts system and for enhancing electromagnetic wave absorber. The wt.% of TiO2 for every composition keep constant is 50% and the ratio of CuO: CDs was various: 45:5, 40:10, and 30:20 for every calcination temperature of CDs. The surface morphology was sticky-tiny-balls-like shape indicating the CDs were attached and sticky surrounds TiO2 and CuO. For the size, the grain distribution increase with increasing calcination temperature which consistent with diffraction spectra, confirm that the CDs were successfully doped in composites TiO2/CuO/CDs. The composite TiO2/CuO/CDs show high electromagnetic wave absorber with efficiency 90% indicated by the reflection loss below -10 dB with working frequency from 5.54 to 6.76 GHz and the bandwidth from 1.4 to 1.8 GHz. The best photocatalytic performance is for TiO2: CuO: CDs is 50: 45: 5 with temperature calcination CDs 250°C which was degraded fipronil pesticide for the concentration of 0.05% up to 62% only for 15 minutes and shows high sta- bility up to fourth cycles. The four-time cycles of pesticide show high stability with degradation >58% indicated that the TiO2/CuO/CDs material, effective and efficient energy for mass production pesticide wastewater. The composite in this study shows high potentials as a new bi functional material with high photocatalytic pesticide performance and absorber electromagnetic waves.