Pr-ZrO/rGO Nanohybrid for Resilient Photocatalytic, Photoluminescence, Forensic, Electrochemical and Biological Applications.

Development of multifunctional heterostructured nanocomposites has received significant attention recently due to their potential applications. In this study, multifunctional zirconium dioxide (ZrO) Praseodymium doped zirconium dioxide (Pr-ZrO) and Praseodymium doped zirconium dioxide decorated reduced graphene oxide (Pr-ZrO/rGO) composites were synthesized using a solution combustion method incorporating Manilkara zapota (M. zapota) fruit juice as a biotemplate. The synthesized nanomaterials were characterized using various analytical techniques, including FTIR, PXRD, UV-DRS, Raman spectroscopy, SEM with EDX, and TEM. Following 60 min of irradiation, the methylene blue (MB) degradation efficiencies of the ZrO, Pr-ZrO, and Pr-ZrO/rGO photocatalysts were found to be 3.38%, 8.02%, and 96.63%, respectively. The photocatalytic degradation efficiency showed a slight decrease from 97% ± 2% in the first cycle to 87% ± 3% by the fifth cycle. The Pr-ZrO/rGO nanocomposite displays a significantly reduced photoluminescence (PL) intensity relative to both Pr-ZrO and pristine ZrO, indicating more efficient separation of photogenerated charge carriers. Pr-ZrO/rGO showed well-defined ridges with highly resolved minute patterns when the latent fingerprints were detected. The Pr-ZrO/rGO nanocomposite exhibited inhibition zones of 12.66 mm against Escherichia coli and 9.33 mm against Staphylococcus aureus. The half-maximal inhibitory concentration (IC) values for the inhibition of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical by ZrO, Pr-ZrO, and Pr-ZrO/rGO were determined to be 4346, 4282, and 4173 μg/mL, respectively. The electrochemical studies showed that the solution resistance (R) of the ZrO electrode was measured at 145.24 Ω, while the Pr-ZrO electrode demonstrated a reduced resistance of 109.95 Ω. Incorporation of Pr into the crystal lattice has reduced the crystallite size and energy gap of ZrO, contributing to its improved characteristics. Reduced graphene oxide offers porosity and conductivity to the photocatalyst and helps in better charge separation. Therefore, this study introduces a novel approach for synthesizing a multifunctional Pr-ZrO/rGO nanohybrid material with potential applications in photoluminescence, latent fingerprint detection, photocatalytic dye degradation, as well as antibacterial and antioxidant activities.