“…Ni and Cu complexes showed a higher bandgap 3.6–4.1 eV in comparison with Ru complexes. This could be due to Ru complexes' higher adsorption capacity, which various researchers in the literature 27 , 28 , 37 , 38 also demonstrated. Figure 2 Diffuse reflectance UV–Vis spectra of Ru-Pth, Ru-Pth-Me, Ni-Pth and Cu-Pth complexes.…”
Selective photochemical oxidation of styrene was performed in an active acetonitrile medium, using H2O2 with or without ultraviolet (UV) light radiation. Pyrithione metal complexes (M–Pth: M = Cu(II), Ni(II), Ru(II); Pth = 2-mercaptopyridine-N-oxide) were used as catalysts. Catalytic testing measurements were done by varying the time, chemical reaction temperature and H2O2 concentration with or without UV energy. Epoxide styrene oxide (SO), benzaldehyde and acetophenone were the major synthesized products. A high batch rate, conversion and selectivity towards SO was shown in the presence of UV. A minor constant formation of CO2 was observed in the stream. Coordinated Ru-based compounds demonstrated the highest process productivity of SO at 60 °C. The effect of the functional alkyl substituent on the ligand Pth, attached to the specific ruthenium(II) centre, decreased the activity of the substance. Ni-Pth selectively yielded benzaldehyde. The stability of the catalysts was examined by applying nuclear magnetic resonance (NMR) spectroscopy and thermogravimetric analysis coupled with mass spectrometry. Tested metal complexes with pyrithione (M–Pth) exhibited excellent reuse recyclability up to 3 cycles.
“…Ni and Cu complexes showed a higher bandgap 3.6–4.1 eV in comparison with Ru complexes. This could be due to Ru complexes' higher adsorption capacity, which various researchers in the literature 27 , 28 , 37 , 38 also demonstrated. Figure 2 Diffuse reflectance UV–Vis spectra of Ru-Pth, Ru-Pth-Me, Ni-Pth and Cu-Pth complexes.…”
Selective photochemical oxidation of styrene was performed in an active acetonitrile medium, using H2O2 with or without ultraviolet (UV) light radiation. Pyrithione metal complexes (M–Pth: M = Cu(II), Ni(II), Ru(II); Pth = 2-mercaptopyridine-N-oxide) were used as catalysts. Catalytic testing measurements were done by varying the time, chemical reaction temperature and H2O2 concentration with or without UV energy. Epoxide styrene oxide (SO), benzaldehyde and acetophenone were the major synthesized products. A high batch rate, conversion and selectivity towards SO was shown in the presence of UV. A minor constant formation of CO2 was observed in the stream. Coordinated Ru-based compounds demonstrated the highest process productivity of SO at 60 °C. The effect of the functional alkyl substituent on the ligand Pth, attached to the specific ruthenium(II) centre, decreased the activity of the substance. Ni-Pth selectively yielded benzaldehyde. The stability of the catalysts was examined by applying nuclear magnetic resonance (NMR) spectroscopy and thermogravimetric analysis coupled with mass spectrometry. Tested metal complexes with pyrithione (M–Pth) exhibited excellent reuse recyclability up to 3 cycles.
“…Ruthenium dye (N719) is the most widely used because it has a good absorbance value for absorbing visible light [4]. However, ruthenium dye is considered quite expensive.…”
The third generation of solar cells is dye-sensitized solar cells (DSSC). DSSC can convert solar energy into electrical energy. The main components of DSSC include working electrode, counter electrode, sensitizer, and electrolyte. Substitution of commercial chemicals for the sensitizer (N719) and the counter electrode (platinum) of DSSC will lower the cost of DSSC fabrication. This study focuses on Nitrogen-Doped Carbon Quantum Dots (N-CQDs) synthesized from rice husks as a sensitizer. Then, DSSC with sensitizer of N719 (Pt-1) and N-CQDs (Pt-2) were compared. Furthermore, the N-CQDs residue in solid carbon was used as the counter electrode material using different sensitizers N719 (C-1) and N-CQDs (C-2). Based on the results, the FTIR characterization of N-CQDs showed the functional groups N-H, O-H, C=O, and CN. The UV-VIS characterization of N-CQDs had absorbance in the wavelength range of 200-400 nm. Pt-2 has an efficiency value of 0.258%, Jsc of 2.188 mA/cm2 Voc of 0.6 volts, and FF of 0.20. C-2 has an efficiency of 0.0010%, Jsc of 0.042 mA/cm2 Voc of 0.131 volts, and FF of 0.17. This confirms that N-CQDs can be used as a sensitizer and counter electrode material, although the results are not as good as commercial chemicals.
“…The researchers apply computational chemistry in defining the structure and electronic properties of dyes without actually synthesizing them. For example, the Time-Dependent Density Functional Theory (TD-DFT) [26] and an ab initio method [27] have been employed for identifying new organic dyes for synthesizing DSSC. TD-DFT is preferred for investi-gating the properties of organic dyes in their excited state due to its higher accuracy and lower computational time than the ab initio method [28,29].…”
The exponentially growing energy requirements and, in turn, extensive depletion of non-restorable sources of energy are a major cause of concern. Restorable energy sources such as solar cells can be used as an alternative. However, their low efficiency is a barrier to their practical use. This provokes the research community to design efficient solar cells. Based on the study of efficacy, design feasibility, and cost of fabrication, DSSC shows supremacy over other photovoltaic solar cells. However, fabricating DSSC in a laboratory and then assessing their characteristics is a costly affair. The researchers applied techniques of computational chemistry such as Time-Dependent Density Functional Theory, and an ab initio method for defining the structure and electronic properties of dyes without synthesizing them. However, the inability of descriptors to provide an intuitive physical depiction of the effect of all parameters is a limitation of the proposed approaches. The proven potential of neural network models in data analysis, pattern recognition, and object detection motivated researchers to extend their applicability for predicting the absorption maxima (λmax) of dye. The objective of this research is to develop an ANN-based QSPR model for correctly predicting the value of λmax for inorganic ruthenium complex dyes used in DSSC. Furthermore, it demonstrates the impact of different activation functions, optimizers, and loss functions on the prediction accuracy of λmax. Moreover, this research showcases the impact of atomic weight, types of bonds between constituents of the dye molecule, and the molecular weight of the dye molecule on the value of λmax. The experimental results proved that the value of λmax varies with changes in constituent atoms and types of bonds in a dye molecule. In addition, the model minimizes the difference in the experimental and calculated values of absorption maxima. The comparison with the existing models proved the dominance of the proposed model.
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