Glycine-A bio-capping agent for the bioinspired synthesis of nano-zinc oxide photocatalyst

• Published in: Journal of materials science. Materials in electronics 2020-02, Vol.31 (4), p.2949-2966
• Main Authors: Basnet, Parita, Samanta, Dhrubajyoti, Chanu, T. Inakhunbi, Jha, Satadru, Chatterjee, Somenath
• Format: Article
• Language: English
• Subjects: Capping; Carboxyl group; Catalytic activity; Characterization and Evaluation of Materials; Chemical precipitation; Chemistry and Materials Science; Crystal lattices; Crystallites; Degradation; Emission spectra; Fourier transforms; Glycine; Lattice parameters; Low temperature; Materials Science; Morphology; Nanoparticles; Nanorods; Optical and Electronic Materials; Photocatalysis; Photocatalysts; Photoluminescence; Rhodamine; Solid phase synthesis; Solid phases; Spectrum analysis; Unit cell; Zinc oxide; Zinc oxides
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-019-02839-z

Structural modification of nanoparticles (NPs) for application-specific study is timely. In the present investigation, an attempt has been made for the bioinspired synthesis of zinc oxide (ZnO) NPs possessing different morphologies using glycine as the bio-capping agent. A variation in the amount of glycine during low-temperature mediated solid-phase synthesis indicated that a higher ratio of glycine directed the ensemble of nanohexagons into nanobundles which further formed nano-flower buds- like morphology, while least concentration formed agglomerated NPs and moderate concentration of glycine was able to modify the NPs’ structure into nanorods. On the other hand, the utilization of solution-phase synthesis methods, i.e. co-precipitation and hydrothermal, led to the formation of thinner and thicker ZnO nanosheets, respectively. In terms of crystalline structure, not much difference was observed in the lattice parameters or the unit cell of the crystal, with approximately similar crystallite sizes. From Fourier transform infrared spectroscopy, the functionalization of glycine from both the amine and the carboxyl group was noted. Further, it was found that the morphology and photoluminescence emission spectra of the samples were inter-related, wherein higher the agglomeration of the particles, greater the intensity of the visible region defect band was observed. The as-synthesized ZnO-photocatalysts were then employed for the degradation of rhodamine B (RhB), a major effluent of the textile industry. The photocatalytic activity of the samples was found to depend upon the surface area, which in turn was related to the morphology and the magnitude of green emission defect states. About 99% RhB degradation was obtained with ZnO possessing nano-flower buds-like morphology within 60 min of sunlight irradiation. Additionally, the role of reactive oxidative species and the stability of this photocatalyst were investigated.