A study on the application of solar cells sensitized with a blackberry-based natural dye for power generation

This research paper is aimed at evaluating the use of natural dyes from blackberry (Rubus glaucus) obtained naturally for their subsequent application in laboratory solar cells to place them in dye-sensitized solar cells (DSSC) for the generation of electrical energy. The problem of the study is the high demand generated by global warming. Natural dyes were used to sensitize six solar cells, which were tested for their ability to absorb ultraviolet and visible light using a spectrophotometer in the ultraviolet-visible range, a solar simulator, and a current-voltage tester. The voltmeter was used to show how much energy each solar cell emitted over eight to 18 hours of daylight, with a required absorbance of 400-500 nm using six solar cells that had been sensitized with natural dyes. To reduce the high demand generated by global warming, use natural dyes from plant species as a supplement to improve efficiency in capturing renewable energy (solar) and converting it into electrical energy. Blackberries are lyophilized and then macerated for one day at room temperature in a dark, cool place to maximize dye's absorption. With two electrodes, the photo and contra, and an electrolyte in between, a Gratzel-type DSSC can be built. Using the doctor blade technique, the titanium dioxide film is added to the fluorine-doped tin oxide (TiO2) in the photoelectrode. By immersion, a natural colourant is then applied. TiO2 glass with a platinum film deposited on it serves as the counterelectrode

Study of the Photocatalytic Degradation of Highly Abundant Pesticides in Agricultural Soils

Organic pesticides are major sources of soil pollution in agricultural lands. Most of these pesticides are persistent and tend to bio accumulate in humans upon consumption of contaminated plants. In this study, we investigate different natural soil samples that were collected from agricultural lands. The samples revealed the presence of 18 pesticides that belong to four different groups including organochlorines (OCP), organophosphorus (OPP), carbamates (Carb), and pyrethroids (Pyrth). The photocatalytic degradation of the five most abundant pesticides was studied in the presence and absence of 1% TiO2 or ZnO photocatalysts under UV irradiation at a wavelength of 306 nm. The five abundant pesticides were Atrazine (OCP), Chlorpyrifos methyl (OPP), Dimethoate (OPP), Heptachlor (OCP), and Methomyl (Carb). The results showed that photolysis of all pesticides was complete under UV radiation for irradiation times between 64–100 h. However, both photocatalysts enhanced photocatalytic degradation of the pesticides in comparison with photolysis. The pesticides were photocatalytically degraded completely within 20–24 h of irradiation. The TiO2 photocatalyst showed higher activity compared to ZnO. The organochlorine heptachlor, which is very toxic and persistent, was completely degraded within 30 h using TiO2 photocatalyst for the first time in soil. The mechanism of photocatalytic degradation of the pesticides was explained and the effects of different factors on the degradation process in the soil were discussed

CO2 Electroreduction over Metallic Oxide, Carbon-Based, and Molecular Catalysts: A Mini-Review of the Current Advances

International audienceElectrochemical CO2 reduction reaction (CO2RR) is one of the most challenging targets of current energy research. Multi-electron reduction with proton-coupled reactions is more thermodynamically favorable, leading to diverse product distribution. This requires the design of stable electroactive materials having selective product generation and low overpotentials. In this review, we have explored different CO2RR electrocatalysts in the gas phase and H-cell configurations. Five groups of electrocatalysts ranging from metals and metal oxide, single atom, carbon-based, porphyrins, covalent, metal–organic frameworks, and phthalocyanines-based electrocatalysts have been reviewed. Finally, conclusions and prospects have been elaborated

Synthesis and Electrocatalytic Activity of Bismuth Tungstate Bi2WO6 for Rhodamine B Electro-Oxidation

International audienceHerein, we have synthesized different BWO samples at different temperatures and evaluated their electrochemical oxidation of Rhodamine B dye in an aqueous medium. The prepared samples were characterized using X-ray diffraction combined with Rietveld refinements, scanning electron microscope coupled with energy dispersive elemental mapping, and thermogravimetric and differential thermal analyses. All the samples crystallize in the orthorhombic Pca21 structure. The crystallite size increased with temperature. The calculated surface areas from the XRD data ranged from 38 to 7 m2 g−1 for BWO-600 to BWO-900, respectively. The optimal BWO loadings on the GCE electrode were 5 × 10−8 mol cm−2 recording the best electrocatalytic efficiency for RhB electrodegradation in 15 min (100%) in 0.1 M of NaCl. The BWO-600 recorded the best activity compared to other BWO samples. The electrocatalytic activity was explained by the high surface area and small crystallite size compared to the other samples. The BWO-600 showed extended electrode reutilization for up to four cycles of reuse under the reported conditions

Probe-Sonicated Synthesis of CuO–ZnO Hybrid Nanocomposite for Photocatalytic and Supercapacitor Applications

An ultrasound-assisted probe sonication route effectively prepared pure CuO and two-dimensional CuO-ZnO nanocomposites (NCs) for different ratios of CuO and ZnO, and the experimental and theoretical methods investigated the structural, photocatalytic, and electrochemical properties. The XRD (X-ray diffraction) patterns revealed a crystallite size (D) range of 25 to 31 nm for pure CuO and CuO-ZnO NCs. According to calculations, the sample’s optical energy bandgap value (Eg) for the NCs is between 1.72 and 2.15 eV. Under UV light irradiation, the photocatalytic discoloration of pure CuO and CuO-ZnO NCs on fast blue (FB) dye was assessed. Under the influence of UV light, the CuO with 10% ZnO composite degrades 83.4% of the dye, which is greater than pure CuO and other NCs. The electrochemical properties of the prepared NCs materials have been studied using cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The specific capacitance values were found to be 248 Fg−1, 301 Fg−1, 352 Fg−1, and 277 Fg−1 for CuO, CuO + 5% ZnO, CuO + 10% ZnO, and CuO + 15% ZnO, respectively, at 1 A/g current density. Galvanostatic charge–discharge tests for these designed NCs show excellent capacitance performance in supercapacitors applications. These innovative results could be considered for expanding novel resources to scale for dual applications in photocatalysis and supercapacitors

Hydrothermally Synthesized Fluorine Added O₃-NaFe_1-xMg_xO₂ Cathodes for Sodium Ion Batteries

The development and study of Na ion batteries are expanding. This study employs the hydrothermal technique to produce single-phase, well-crystallized, fluorine-added O3-type NaFe1-xMgxO2. Using XRD, FESEM, and HRTEM, the sample’s phase structure and morphological information were characterized. Initially, without adding fluorine the electrode suffers from poor stability at high voltage ranges and also during long-term cycling. So, fluorine was added to the structure and the electrochemical performance of the material was greatly increased. The electrochemical performance of O3-type positive electrode materials for rechargeable Na ion batteries is evaluated. The capacity of fluorine-added O3-type NaFe1-xMgxO2 is approximately 163 mAh g−1 (50 mA g−1). Adding fluorine to the host structure increases the stability of the electrode, leading to improved electrochemical performance during long-term cycling. The electrochemical results indicate that fluorine-added O3-type NaFe1-xMgxO2 cathode material for cost-effective and environmentally friendly sodium-ion batteries is promising. Fluorine-based electrodes will be a future for Na ion energy storage device

Atomic Orbital Search Algorithm for Efficient Maximum Power Point Tracking in Partially Shaded Solar PV Systems

The efficient extraction of solar PV power is crucial to maximize utilization, even in rapidly changing environmental conditions. The increasing energy demands highlight the importance of solar photovoltaic (PV) systems for cost-effective energy production. However, traditional PV systems with bypass diodes at their output terminals often produce multiple power peaks, leading to significant power losses if the optimal combination of voltage and current is not achieved. To address this issue, algorithms capable of finding the highest value of a function are employed. Since the PV power output is a complex function with multiple local maximum power points (LMPPs), conventional algorithms struggle to handle partial shading conditions (PSC). As a result, nature-inspired algorithms, also known as metaheuristic algorithms, are used to maximize the power output of solar PV arrays. In this study, we introduced a novel metaheuristic algorithm called atomic orbital search for maximum power point tracking (MPPT) under PSC. The primary motivation behind this research is to enhance the efficiency and effectiveness of MPPT techniques in challenging scenarios. The proposed algorithm offers several advantages, including higher efficiency, shorter tracking time, reduced output variations, and improved duty ratios, resulting in faster convergence to the maximum power point (MPP). To evaluate the algorithm’s performance, we conducted extensive experiments using Typhoon HIL and compared it with other existing algorithms commonly employed for MPPT. The results clearly demonstrated that the proposed atomic orbital search algorithm outperformed the alternatives in terms of rapid convergence and efficient MPP tracking, particularly for complex shading patterns. This makes it a suitable choice for developing an MPP tracker applicable in various settings, such as industrial, commercial, and residential applications. In conclusion, our research addresses the pressing need for effective MPPT methods in solar PV systems operating under challenging conditions. The atomic orbital search algorithm showcases its potential in significantly improving the efficiency and performance of MPPT, ultimately contributing to the optimization of solar energy extraction and utilization

Design of Bismuth Tungstate Bi2WO6 Photocatalyst for Enhanced and Environmentally Friendly Organic Pollutant Degradation

In this study, a chemical precipitation approach was adopted to produce a photocatalyst based on bismuth tungstate Bi2WO6 for enhanced and environmentally friendly organic pollutant degradation. Various tools such as X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), optical spectroscopy and X-ray photoelectron spectroscopy, were employed to assess the structural and morphological properties. Hence, the XRD profiles showed a well crystallized Bi2WO6 orthorhombic phase. The photocatalytic performance of the resulting photocatalyst was assessed by the decomposition of Rhodamine B (RhB) and methyl orange (MO) with a decomposition efficiency of 97 and 92%, along with the highest chemical oxygen demand of 82 and 79% during 120 min of illumination, respectively. The principal novelty of the present work is to focus on the changes in the crystalline structure, the morphology, and the optical and the photoelectrochemical characteristics of the Bi2WO6, by tuning the annealing temperature of the designed photocatalyst. Such physicochemical property changes in the as-prepared photocatalyst will affect in turn its photocatalytic activity toward the organic pollutant decomposition. The photocatalytic mechanism was elaborated based on electrochemical impedance spectroscopy, photocurrent analysis, photoluminescence spectroscopy, and radical trapping measurements. The overall data indicate that the superoxide O2•− and holes h+ are the principal species responsible for the pollutant photodegradation

Current advances on nanostructured oxide photoelectrocatalysts for water splitting: A comprehensive review

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Bismuth Silver Oxysulfide for Photoconversion Applications: Structural and Optoelectronic Properties

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