Boosted ultrasound-sunlight-driven removal of organic pollutant over double Z-scheme plasmonic ZnO–Cu–CuO/g-C3N4 nanophotocatalyst: design via in-situ co-precipitation hybrid with various sonication powers

Abstract

Herein, the sonophotocatalytic degradation of the organic pollutant is studied over double Z-scheme plasmonic ZnO–Cu–CuO hybridized two-dimensional C3N4, which is designed with an in-situ co-precipitation manner hybrid with sonicated irradiation. The sonication power effect on semiconductor properties is studied at P = 0, 30, 60, and 90 W, and the sonophotocatalysis test is done at constant power (P = 60 W) and simulated sunlight irradiation in order to find optimal properties. XRD, FESEM, 3D texture, TEM, EDX, BET–BJH, and DRS were used to determine the physicochemical characteristics and ultrasound effect on nano semiconductors. XRD analysis shows that Cu nanoparticles have been observed in heterostructured catalysts synthesized by ultrasound waves, except ZnO–Cu–CuO/C3N4 (P = 0). And with an increase in sonication power, the intensity of plasmonic Cu particles decreased. According to FESEM and 3D texture analysis, the surface roughness is reduced, which shows nanoparticles' good-fit nucleation and dispersion. More importantly, the total pore volume for ZnO–Cu–CuO/g-C3N4 (P = 0) and ZnO–Cu–CuO/g-C3N4 (P = 90) is 0.076 and 0.096 cm3/g, respectively in which the mesopores volume for ZnO–Cu–CuO/g-C3N4 (P = 90) sample (0.0622cm3/g) is more, facilitating the penetration of pollutants and products. DRS revealed that by increasing Cu nanoparticles, the band gap of ZnO–Cu–CuO/C3N4 (P = 90) is tuned in the visible-light region (Eg = 1.54 eV). The highest sonophotocatalytic degradation of 20 mg/L of methylene blue was obtained at 97.9% over ZnO–Cu–CuO/C3N4 (P = 90) and 60 W ultrasound irradiation, after 120 min of sonophotocatalysis treatment.