Utilization of Low-Cost Waste Tea-Derived CuO Nanoparticles for Enhanced Photocatalytic Decomposition of Rhodamine B Dye Under Visible Light Irradiation

Photocatalytic degradation of Orange G on nitrogen-doped TiO 2 catalysts under visible light and sunlight irradiation

Anatase/brookite biphasic surface fluorinated Fe–TiO2 photocatalysts to enhance photocatalytic removal of VOCs under visible and UV light

Fulgide Derivative-Based Solid-State Reversible Fluorescent Switches for Advanced Optical Memory

The photocatalytic degradation of the organic pollutants using the green synthesized catalysts is an environmentally safe approach for the wastewater treatment. In this study, ZnO and CuO nanoparticles (NPs) and ZnO/CuO nanocomposites (NCs) with various CuO weight percents were synthesized using extract of Musa acuminata fruit peel as the stablizing and capping agent. The synthesized nanomaterials were characterized by TGA/DTA, XRD, SEM, TEM, SAED, HR-TEM, UV-DRS and FTIR techniques. The degradation of methylene blue (MB) dye using the synthesized catalysts was investigated under a visible light source. XRD analysed average crystalline sizes were 24.9, 17.0 and 22.6 nm for ZnO, CuO, and ZnO/CuO nanomaterials, respectively. The SEM and TEM analysis confirms that ZnO NPs, CuO NPs, and ZnO/CuO NCs possessed the spherically shaped monoclinic structure. The bandgap energies of ZnO NPs, CuO NPs and ZnO/CuO NCs were found to be 3.25, 1.7 and 3.18 eV respectively. The FT-IR analysis confirms presence of various reducing and capping agents. The photocatalytic activities of ZnO NPs, CuO NPs, and ZnO/CuO NCs were evaluated using the degradation of MB dye under the visible light irradiation. The photocatalysts CuO, ZnO, and ZnO/CuO exhibited the degradation efficiencies of 50%, 57%, and 90%, respectively.

Simple SummaryThe polyphagous agricultural pest Spodoptera frugiperda (J.E. Smith) has a high level of chemical pesticide resistance. This study’s objective is to create and assess the effectiveness of CuO NPs (copper oxide nanoparticles) with a variety of tests against S. frugiperda for larvicidal, antifeedant, immunological, and enzymatic activities. Energy dispersive X-ray (EDaX) analysis and a scanning electron microscope (SEM) were used to analyze copper nanoparticles for the identification of physical and chemical properties. The CuO NPs demonstrated high larvicidal and antifeedant activity. The CuO NPs treatment significantly reduced the number of larval hemocytes 24 h after treatment when compared to the control; hemocyte counts and sizes also varied. The levels of larval acetylcholinesterase enzyme levels were decreased with dose-dependent activity after 24 h of treatment with CuO NPs. The current research conclusively shows that CuO NPs have remarkable larvicidal antifeedant activity.This study aimed to synthesize and evaluate the efficacy of CuO NPs (copper oxide nanoparticles) with varying test concentrations (10–500 ppm) against larvicidal, antifeedant, immunological, and enzymatic activities against larvae of S. frugiperda at 24 h of treatment. Copper nanoparticles were characterized by using a scanning electron microscope (SEM) and energy dispersive X-ray (EDaX) analysis. The EDaX analysis results clearly show that the synthesized copper nanoparticles contain copper as the main element, and the SEM analysis results show nanoparticle sizes ranging from 29 to 45 nm. The CuO NPs showed remarkable larvicidal activity (97%, 94%, and 81% were observed on the 3rd, 4th, and 5th instar larvae, respectively). The CuO NPs produced high antifeedant activity (98.25%, 98.01%, and 98.42%), which was observed on the 3rd, 4th, and 5th instar larvae, respectively. CuO NPs treatment significantly reduced larval hemocyte levels 24 h after treatment; hemocyte counts and sizes changed in the CuO NPs treatment compared to the control. After 24 h of treatment with CuO NPs, the larval acetylcholinesterase enzyme levels decreased with dose-dependent activity. The present findings conclude that CuO NPs cause remarkable larvicidal antifeedant activity and that CuO NPs are effective, pollution-free green nano-insecticides against S. frugiperda.

Cobalt-doped cerium oxide nanoparticles: Enhanced photocatalytic activity under UV and visible light irradiation

The present study involves the synthesis of neodymium-doped zinc oxide nanoparticles decked multiwalled carbon nanotubes (Nd-ZnO-MWCNTs) with different weight percentage compositions of Nd through the co-precipitation method. The synthesized photocatalysts were utilized in photocatalytic removal of acid blue 40 and eosin Y dye solutions via visible light irradiation. The influence of catalyst dose and dye concentrations on the degradation efficiency was also studied. The catalysts were characterized using XRD, FTIR, BET surface area analysis, UV–Vis and TEM spectroscopies. TEM revealed that the Nd-ZnO nanoparticles were well distributed on the MWCNTs surface. XRD analysis showed that the ZnO occurred in the wurtzite phase. The introduction of Nd and MWCNTs reduced the band gap of ZnO from 3.2 to 2.7 eV resulting in its enhanced visible light absorption. All the modified ZnO photocatalysts degraded the dye at higher efficiencies compared to the bare ZnO with 0.6% Nd-ZnO-MWCNTs being the most effective. The bare ZnO degraded 13% of acid blue 40 dye while 0.6% Nd-ZnO-MWCNTs exhibited 99% degradation efficiency. The synergistic effect of Nd and MWCNTs was identified to be responsible for the enhanced efficiency of the Nd-ZnO-MWCNTs photocatalysts.

Cu2O nanoparticles decorated BiVO4 as an effective visible-light-driven p-n heterojunction photocatalyst for methylene blue degradation

Fabrication of heterojunction semiconductors for the photodegradation of toxic organic dyes under sunlight exposure has earned significant recognition from researchers nowadays. On that account, we have synthesized and explored a comparative photodegradation study of ZnO/CuO nanocomposite with ZnO and CuO nanoparticles. ZnO and CuO nanoparticles have been synthesized by biosynthesis methods usingFicus benghalensisleaf extract. As-synthesized ZnO and CuO nanoparticles have been further utilized for the synthesis of ZnO/CuO nanocomposite by the mortar pestle crushing/milling method. Both biosynthesis methods and mortar pestle crushing/milling methods are simple, low-cost, and environmentally friendly. Structural, optical, and morphological analysis of all the synthesized nanomaterials havebeen doneby powder X-ray diffraction (PXRD), scanning electron microscopy (SEM),transmission electron microscopy (TEM),Brunauer-Emmett-Teller (BET),field emission scanning electron microscopy (FESEM), energy-dispersive spectroscopy (EDS), fourier transform infrared spectroscopy (FTIR), and UV-visible spectroscopy.PXRD data reveal that synthesized ZnO nanoparticles are in the hexagonal wurtzite phase, CuO nanoparticles in the monoclinic phase, and ZnO/CuO nanocomposite in the hexagonal wurtzite as well as in monoclinic phase. FE-SEM and TEM images of ZnO/CuO nanocomposite reveal the nanorod-shaped morphology along with micro-sized and nano-sized flakes. The BET analysis shows the surface areas 18.128 m2/g for ZnO nanoparticles, 16.653 m2/g for CuO nanoparticles, and 19.580 m2/g for ZnO/CuO nanocomposite, respectively. Theenergyband gap values of ZnO/CuO nanocomposite are obtained 3.13eV for ZnO and 2.76eV for CuO, respectively. The photocatalytic behaviors of all the synthesized nanomaterialsareexamined against aqueous dye solutions of methylene blue (MB), rhodamine B (RhB), and methyl orange (MO) under sunlight irradiation. The results reveal that the photocatalytic degradation efficiency of ZnO/CuO nanocompositehasbeen found higher than with ZnO and CuO nanoparticles for all the dyes. Also, all the synthesized nanomaterialsindicatehigher photocatalytic degradation efficiency for methylene blue dye among allthreedyes. The kinetics of photodegradation of all the dye solutions has also been investigated in the presence of ZnO, CuO, and ZnO/CuO photocatalysts separately. The results exhibit that rate constant values for all the dyes are higher with ZnO/CuOnanocompositethan with ZnO and CuOnanoparticles.ZnO/CuO nanocomposite demonstrates degradation efficiency for MB dye99.13%, for RhB80.21%, and for MO67.22%after 180min of sunlight exposure.ZnO/CuO nanocomposite and ZnO and CuO nanoparticles also show thebestreusability and stability up to three cycles for photocatalytic degradation of MB dyes amongall the dyes.Therefore, green synthesized ZnO/CuO nanocomposite could be used asan efficientphotocatalyst for the degradation of various toxic dyes.The mineralization of different dyes using ZnO/CuO nanocomposite has been examined by FTIR analysis. Furthermore, the mineralizationof MB dye has been done by total organic carbon (TOC)measurements.

Efficiency of neonicotinoids photocatalytic degradation by using annular slurry reactor

Facile synthesis, characterization and photocatalytic performance of Au-Ag alloy nanoparticles dispersed on graphitic carbon nitride under visible light irradiations

Evaluation of N-doped graphene role in the visible-light driven photodegradation of sulfamethoxazole by a TiO2-silver-graphene composite

Efficient photocatalytic degradation of organic dyes over titanium dioxide coating upconversion luminescence agent under visible and sunlight irradiation

Enhanced photocatalytic activity in RhB dye degradation by Mn and B co-doped mixed phase TiO2 photocatalyst under visible light irradiation

Introduction: The green synthesis of nanomaterials offers notable advantages like environmental sustainability, low toxicity, and cost-effectiveness. Herein, Eryngium foetidum leaf extract was used for green synthesis of CuO and ZnO nanoparticles (NPs). Materials and methods: The synthesized NPs, yielded approximately 2 grams after being calcined for 6 hours at 400ºC. They were characterized by UV-vis spectroscopy, FTIR, XRD, FESEM, TEM, and EDX analysis. UV-V initially confirmed the formation of nanoparticles is spectroscopy, which showed λmax at 356 nm and 364 nm for CuO NPs, ZnO NPs, respectively. Results: The results of TEM analysis displayed that the prepared CuO and ZnO NPs were elliptical and rod-shaped, having particle sizes of 50.02 nm and 31.95 nm, respectively. Discussion: FTIR and HPLC analysis showed involvement of various polyphenols, including chlorogenic acid and quercetin, available in the leaf extract of E. foetidum, in the reduction and stabilization of Cu2+ to Cu0 and Zn2+ to Zn0. The synthesized nanoparticles exhibited strong anti- bacterial activities against four pathogenic bacterial strains, namely Enterbacter aerogenes, Staphylococcus aureus, Escherichia coli, and Bacillus subtilis; however, CuO NPs (E. coli, 38.5 mm>E. aerogenes, 29.25 mm>B. subtilis, 29.03 mm>S. aureus, 28.0 mm) exhibited higher antimicrobial activities than the ZnO NPs (B. subtilis, 22 mm>E. coli, 16 mm>S. aureus, 15 mm>E. aerogenes, 14.15 mm). Additionally, both the synthesized nanoparticles displayed good antioxidant activities with IC50 of 1.87 mg/mL for CuO NPs, and 0.985 mg/mL for ZnO NPs. Conclusion: The results showed that the synthesized CuO NPs and ZnO NPs can be used as promising antimicrobial agents, and antioxidants.