Influence of β-CD and Ag deposition over TiO2 towards photocatalytic oxidation of urea under solar irradiation

Abstract

Photocatalytic oxidation of urea is an essential area of study for converting urea to nitrate. As crops absorb nitrogen in the form of NO3− but due to incomplete oxidation, a substantial fraction of it escapes into the atmosphere as N2. Hence, an effective photocatalyst is urgently needed to improve nitrate conversion. This study focuses on the influence of β-cyclodextrin and Ag deposition on TiO2 towards the photocatalytic oxidation of urea. β-cyclodextrin (15–25 wt%) and Ag(1–3 wt%) loaded binary and ternary nanocomposites have been prepared using hydrothermal and photodeposition methods, respectively. The binary and ternary hybrids were characterized using FESEM, EDX, HR-TEM, XRD, XPS, DRS, PL, DLS, and FT-IR analysis. Photocatalytic urea degradation activity was evaluated under solar irradiation. The β-CD25/TiO2@Ag1 ternary nanocomposites show 78% degradation efficiency with 17.8% nitrate yield after 180 min reaction time which is the highest. This observation can be ascribed to the higher affinity of β-CD towards N2 due to the hydrophobic effect and the surface plasmon effect of Ag, which amplifies its visible light response. Such observations will attract much interest from a large section of material and agricultural chemists to design new catalysts for photochemical urea oxidation to afford sustainable agriculture.