Synthesis and characterization of heterostructured nanoparticle for efficient photocatalytic performance for dye degradation

This paper focusses on the synthesis of cobalt vanadate (CoVO4) nanoparticles (NPs) by precipitation method. This was further augmented by assistance from microwave. Nanotechnology has been a wonderful tool with the promising application in different fields of life. The CoVO4 NPs synthesized by microwave assisted precipitation method was characterized by advanced techniques such as X-ray powder diffraction (XRD), Energy dispersive X-ray analysis (EDX), Scanning electron microscopy (SEM), Ultraviolet visible spectroscopy (UV–vis) techniques. Rhodamine B (RhB) dye was used to evaluate the photo catalytic activity (PCA) of NPs by degradation of dye. The conditions were optimized for maximum degradation of dye. The NPs were in the nano flowers form and the size was ≤100 nm. The results regarding degradation of RhB was through PCA were promising; 83% dye was degraded at pH 10, reaction time 160 min and catalyst dose 1 g. It may conclude that the synthesized NPs could further be employed for possible treatment of industrial effluents particularly textile industry.

Theoretical Investigation of Perylene Diimide derivatives as Acceptors to Match with Benzodithiophene based Donors for Organic Photovoltaic Devices

Optoelectronic properties of PDI derivatives (PDI-1–PDI-28) have been studied by inserting functional groups (–CN, –NO2 and –SO2) at different positions, by using DFT and TD-DFT functional at CAM-B3LYP/6-31 (d) level of theory. Absorption spectra of investigated PDI derivatives cover whole UV-Visible region which indicate that studied molecules could be used efficiently for photovoltaics. The R*(λmax – λmin) value of PDI derivatives is red shifted due to CN substitution while it resulted in slightly blue shift due to NO2 substitution. In addition, reorganization energy (λ) values found to be lowered by all substituents but more efficiently by SO2 and CN substituents. Molecular electrostatic potential surfaces and chemical reactivity indices have also been calculated to verify results. Furthermore, investigated acceptor molecules have been matched with suitable donors (based on benzo [2.1-b:3.4-b′] dithiophene derivatives D1–D5) to verify their practical efficiency. The calculated open circuit voltage (Voc) of investigated PDI derivatives is fairly high with donors D1 (0.95–1.34) and D2 (0.54–0.92). This study can be beneficial in future investigations of donor-acceptor materials for organic photovoltaic devices.

Exploring the Effect of Electron Withdrawing Groups on Optoelectronic Properties of Pyrazole Derivatives as Efficient Donor and Acceptor Materials for Photovoltaic Devices

Multifunctional pyrazole derivative, i.e. 3-amino-1-(5-hydroxy-3-methyl-1H-pyrazol-4-yl)-1H-benzo[f]chromene-2-carbonitrile (PBCC) has been synthesized and characterized. To shed light on various properties of interests, the ground state geometry was optimized by adopting Density Functional Theory (PBE/TZ2P). The effect of different functionals on the absorption wavelengths was studied by using Time-Domain DFT (TDDFT), e.g. GGA functional PBE, hybrid functionals B3LYP and PBE0, rang separated functionals CAM-B3LYP, LCY-PBE and CAMY-B3LYP, Dispersion Corrections PBE-D3 and B3LYP-D3. Among all these functionals PBE and PBE-D3 were found to be good choices which reproduced the absorption spectra of the PBCC. With the aim to enhance the electro-optical, charge transfer and photovoltaic properties, five new derivatives were designed by di-substituting the –F, –Cl, –Br, –COOH and –CN at benzochromene moiety. The electron injection barrier, band gap alignment and related calculated photovoltaic parameters revealed that PBCC and its newly designed derivatives would be proficient to be used in photovoltaic devices. These compounds can be used as donor materials in dye-sensitized solar cells (DSSCs) with favorable type-II band alignment. Moreover, PBCC and most of its derivatives might also be good choice as efficient acceptors with poly(dithieno[3,2-b:2,3-d]pyrrole thiophene) (PDTPr-T) and donor materials with Phenyl-C61-butyric acid methyl ester (PC61BM) in organic solar cells.

A Novel Approach for Modification of Biosorbent by Silane Functionalization and its Industrial Application for Single and Multi-Component Solute System

The potential of an economically cheap raw material (rice husk) was evaluated in the present study to remove dyes including reactive yellow 15 (RY15) and reactive red 241 (RR241) in single and multi-component systems. The adsorbent was modified and functionalized chemically using glycidoxypropyltrimethoxysilane, sulfur and silane to enhance the removal efficiency of pollutants. The modified rice husk was evaluated by scanning electron microscope (SEM) and Fourier transform Infrared Spectroscopy (FTIR). Batch adsorption study showed that the modified rice husk with silane graft (RHSi) had highest removal efficiency of both dyes with 20% more removal compared to raw rice husk. The sorption correlated well with Langmuir, Freundlich, SIPS and Redlich-Peterson models for adsorption. Highest sorption was obtained at 10 mg L−1 of dye, 50 °C, 200 mg g−1 of adsorbent dose and pH 4. The mixture of two dyes poorly fit to the original Langmuir but fit best to the Langmuir-like model. This indicates that competitive Langmuir-like model considers that the capacities of adsorbents are equal. Results showed that the components compete for the available binding sites on adsorbent surface. It was also indicated that silane grafting can offer comparatively more binding sites compared to the raw rice husk and single-solute isotherm parameters cannot used for multi-component solute system.