The green approach of ZnO NPs and its Antioxidant, hemolytic, and photocatalytic activity and functionalized r-GO-ZnO for energy storage application

Green route to fabrication of Semal-ZnO nanoparticles for efficient solar-driven catalysis of noxious dyes in diverse aquatic environments

“…The peaks observed at 3,855 cm -1 to 3,017 cm -1 were interpreted as the sharp stretching vibrations of the O-H group in water, alcohol, and phenol present in the Semal leaf extract ( Abdullah et al, 2023 ; Elbrolesy et al, 2023 ). The O=C=O strong stretching of carboxylic acid was observed at 2392 cm -1 and 2328 cm -1 ; the C=C medium stretching of the alkane groups was attributed to the band at 1,460 cm -1 ( Meena et al, 2023 ), and the bands at 1,382 cm -1 and 874 cm -1 were associated with C-O strong stretching in the aliphatic ether compounds and C-H strong banding in the 1,3-disubstituted compounds, respectively ( Vinayagam et al, 2020 ). The strong sharp peak at 522 cm -1 accompanying the Zn-O stretching vibrations in the spectrum verified the formation of the Semal-ZnO NPs ( Lanjwani et al, 2023 ; Supin et al, 2023 ).…”

“…HR-TEM was used to ascertain the sizes, shapes, and crystalline makeup of the phytofabricated NPs, and the resulting electron micrographs exhibit that the Semal-ZnO NPs are spherical with an average size of 17 nm ( Figures 3A,B,E ), which is in line with the findings of some recent literature ( Kamaraj et al, 2022 ; Sreelekshmi et al, 2023 ; Tejaswini et al, 2023 ; Yassin et al, 2023 ). The micrographs show a homogeneous distribution, but agglomeration of the Semal-ZnO NPs was also visible ( Abdullah et al, 2023 ; Meena et al, 2023 ), probably owing to the elevated surface energy of the NPs and chemical makeup of the surface-bound capping and reducing agents ( Abdullah et al, 2023 ). Furthermore, there is a propensity for the NPs to attract each other and form larger clusters in an aqueous medium, thereby altering the properties of the synthesized materials ( Alprol et al, 2023 ).…”

“…The hydroxyl radicals produced are very powerful oxidizers, and they react with the dye molecules along with other oxidant species such O 2 • - and HO 2 . to produce the degradation products ( Alharthi et al, 2020 ; Golmohammadi et al, 2020 ; Aldeen et al, 2022 ; Albo Hay Allah and Alshamsi, 2023 ; Meena et al, 2023 ). …”

“…The photocatalytic activities of the biogenic NPs are attributed to their specific surface chemistry and morphologies, which facilitates generation of ROS upon exposure to light ( Gul et al, 2023 ). The unique properties of these biogenic NPs offer numerous advantages, such as biocompatibility, reduced toxicity, and enhanced catalytic efficacy, making them well suited for catalytic photodegradation of harmful dyes ( Aaga and Anshebo, 2023 ; Malik et al, 2023 ; Meena et al, 2023 ). In the present study, an aqueous leaf extract of the Semal tree was used to synthesize zinc oxide (Semal-ZnO) NPs in an environmentally friendly manner.…”

Green supercapacitors: review and perspectives on sustainable template-free synthesis of metal and metal oxide nanoparticles

“…The electrochemical analysis of the prepared reduced graphene oxide with zinc oxide (rGO-ZnO) nanocomposite revealed that it has a high specific capacitance of about 667 F g −1 in comparison to the pure zinc oxide nanoparticles (200 F g −1 ) and good cycling stability over 1000 cycles in KOH medium. 108 Additionally, the synthesized ZnO NPs showed good biocompatibility. Saini et al 109 synthesized ZnO using the seed and bark of Azadirachta indica for antibacterial, photocatalytic, and supercapacitor applications.…”