Graphene oxide decorated BiOI/CdS nanocomposite: An efficient ternary heterostructure for photodegradation and adsorption study of organic pollutants

This study presents a ternary heterostructure comprising graphene oxide (GO) decorated BiOI/CdS, as a highly effective candidate for both the photodegradation and adsorption of organic pollutants. The composite materials were synthesized through a facile solvothermal method. The structural and morphological characteristics of the synthesized materials were thoroughly analyzed using various analytical techniques. Photoluminescence (PL) spectral analysis of the photocatalysts emphasises the strong charge-carrier separations in ternary composites, which is the main requirement for enhancing degradation performances. The photocatalysts were utilized to remove the methylene blue (MB) and doxycycline (DC) from aqueous suspensions. The most effective ternary composite (GO/BiOI/CdS-x, x = 0.4 mmol CdS) resulted in 99.2% degradation of MB within 25 min and 83.7 % degradation of DC within 150 min of light exposure. Trapping experiments identified O2 center dot- and h+ as the most active species in pollutant degradation. A Z-scheme mechanism, supported by Mott-Schottky plots, VB-XPS spectra, and active species observations, was proposed to elucidate degradation processes. Additionally, the GO/BiOI/CdS-0.4 ternary composite demonstrated impressive adsorption ability for MB, indicating its robust pollutant removal capability. The composite also demonstrated remarkable stability and an impressive ability to be reused, positioning it as a highly promising material for use in wastewater treatment.