Bio-functionalized, elongated hexagonal bi-pyramidal, citrus limetta/ZnO nanostructures as potential photocatalytic and seed germinating agents

In this research, the photocatalytic and seed germination potentials of bio-functionalized, as-synthesized zinc oxide (ZnO) nanoparticles (NPs) were investigated. ZnO NPs were created by reducing zinc acetate hexahydrate with a citrus limetta (C. limetta) peel extract. The hexagonal wurtzite crystal was observed in C. limetta/ZnO NPs, with crystallite diameters ranging from 50 to 60 nm and an energy-band gap of 3.08 eV. Fourier-transform infrared spectrum confirmed the presence of phytochemicals from C. limetta on the surface of the resultant ZnO. The unique, elongated hexagonal bi-pyramidal nanostructures were spread evenly across a vast region, as validated by High-resolution transmission electron microscopy and field emission scanning electron microscope. The highly porous microstructure of C. limetta/ZnO and its large specific surface area of 80.72 m2 g−1 were established by Brunauer–Emmett–Teller analysis. The catalytic performance of C. limetta/ZnO for the decomposition of the industrial reactive yellow 18 dye (RY18) was examined. Under UV light, RY18 dye could be broken down by more than 98% in 100 min. With a minimal energy consumption of 4.34 × 1022 J mol−1, the C. limetta/ZnO NPs demonstrated excellent performance (a quantum yield of 1.79 × 10−4Ϣ and a figure-of-merit of 2.92 × 10−10 mol l J−1g−1h−1). The seed germinating capability of C. limetta/ZnO was investigated first time for the Brassica juncea crop. The germination and development of Brassica juncea seed were greatly enhanced by priming with C limetta/ZnO. Hence, C. limetta/ZnO NPs are identified as photocatalytic and seed-germinating agents with remarkable efficiency.