Porous carbons are highly attractive and demanding materials which could be prepared using biomass waste; thus, they are promising for enhanced electrochemical capacitive performance in capacitors and cycling efficiency in Li-ion batteries. Herein, biomass (rice husk)-derived activated carbon was synthesized via a facile chemical route and used as anode materials for Li-ion batteries. Various characterization techniques were used to study the structural and morphological properties of the prepared activated carbon. The prepared activated carbon possessed a carbon structure with a certain degree of amorphousness. The morphology of the activated carbon was of spherical shape with a particle size of ~40–90 nm. Raman studies revealed the characteristic peaks of carbon present in the prepared activated carbon. The electrochemical studies evaluated for the fabricated coin cell with the activated carbon anode showed that the cell delivered a discharge capacity of ~321 mAhg⁻¹ at a current density of 100 mAg⁻¹ for the first cycle, and maintained a capacity of ~253 mAhg⁻¹ for 400 cycles. The capacity retention was found to be higher (~81%) with 92.3% coulombic efficiency even after 400 cycles, which showed excellent cyclic reversibility and stability compared to commercial activated carbon. These results allow the waste biomass-derived anode to overcome the problem of cyclic stability and capacity performance. This study provides an insight for the fabrication of anodes from the rice husk which can be redirected into creating valuable renewable energy storage devices in the future, and the product could be a socially and ethically acceptable product.

In this work, a fast, environment-friendly and economic route was used to prepare ZnO and their nanocomposites containing reduced graphene oxide (RGO) and carbon nanotubes (CNTs) for the fabrication of dye-sensitized solar cells (DSSCs). The prepared nanostructures were well-characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Raman measurements. The XRD, Raman and TEM results confirmed that the ZnO nanostructures were crystallized into the hexagonal phase, and the nanocomposites containing RGO and CNTs. Morphological studies performed by using FESEM and TEM images showed that the ZnO possessed tube-like morphology with length and diameter in the range of ~1 micron and 90–200 nm, respectively, which were uniform and densely covered on the surface of the carbon materials. The DSSCs were fabricated using prepared nanostructures as a working electrode and platinum as a counter electrode with ruthenium-based dyes and iodide electrolytes. To further improve the efficiency of fabricated solar cells, nanocomposites of prepared nanostructures of ZnO with RGO and CNTs were synthesized, and their results were compared with the pristine samples. The results showed that the ZnO/CNTs (0.5 wt%) nanocomposites electrode exhibited the highest power conversion efficiency (PCE) of DSSCs with a maximum value of 0.612% compared to 0.326% of DSSC with pure ZnO, and 0.574% of DSSC with ZnO/RGO. Significantly, this technique could be used for large-scale production using the existing economical and highly effective DSSC fabrication technique.

In this study, copper and tin doped TiO₂ nanocomposite (NCs) (Cu-Sn-TiO₂) were sunthesized using a precipitation method and their potential for nanoremediation of pesticide residues in soil was investigated. To characterize the physicochemical properties of the Cu-Sn-TiO₂ NCs, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy were used. To assess their antibacterial activity against Escherichia coli and Staphylococcus aureus, bacterial growth inhibition and bacterial membrane damage were measured. The photocatalytic experiment was conducted under natural climatic sunlight. The soil samples were hand-spread to a height of 5 mm in a glass tray and sprayed with an aqueous pesticide solution. The catalyst concentration that worked best was 0.01%. Validated UFLC with PDA detection was used to quantify the samples. Kinetic parameters such as rate constant (k) and DT50 were calculated using pesticide residue dissipation data. After 20 h of exposure, the Cu–Sn–TiO₂ NCs demonstrated significant antibacterial activity, reducing bacterial viability by more than 70%. Based on the formation of reactive oxygen species and the disruption of the bacterial membrane, the mechanism of the antibacterial and photocatalytic action of the Cu–Sn–TiO₂ NCs was discussed. The agricultural and environmental sectors may benefit from the Cu–Sn–TiO₂ NCs promising potential for the nanoremediation of pesticide residues in soils.

In this study, we synthesized copper and tin doped TiO₂ nanoparticles (NPs) (Cu-Sn-TiO₂) using a precipitation method and investigated their potential for nanoremediation of pesticide residues in soil. To characterize the physicochemical properties of the Cu-Sn-TiO₂ NPs, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy were used. To assess their antibacterial activity against Escherichia coli and Staphylococcus aureus, we measured bacterial growth inhibition and bacterial membrane damage. We also used simulated solar irradiation to test their photocatalytic degradation of two commonly used pesticides, tebuconazole and trifloxystrobin soils. Cu-Sn-TiO₂ NPs outperformed pure TiO₂ in terms of visible light absorption, electron-hole recombination, antibacterial and photocatalytic performance. For both copper and tin, 0.01% was determined to be the ideal doping concentration. Within 20 hours, the Cu-Sn-TiO₂ NPs degraded tebuconazole and trifloxystrobin in soils by more than 50%. The acquired samples were quantified using validated UFLC with PDA detection. Kinetic parameters such as rate constant (k) and DT50 were calculated using pesticide residue dissipation data. After 20 hours of exposure, the Cu-Sn-TiO₂ NPs demonstrated significant antibacterial activity, reducing bacterial viability by more than 70%. Based on the formation of reactive oxygen species and the disruption of the bacterial membrane, the mechanism of the antibacterial and photocatalytic action of the Cu-Sn-TiO₂ NPs was discussed. The agricultural and environmental sectors may benefit from the Cu-Sn-TiO₂ NPs promising potential for the nanoremediation of pesticide residues in soils.