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Supercapacitors are becoming more popular in the field of energy storage day by day. Thanks to their superior features such as fast charge–discharge, high capacities, and stable structures. Especially, supercapacitors designed using biomass as the electrode material are more preferred in this field because they are cheap, abundant, environmentally friendly, high capacity, and have a long cycle life. In this study, two supercapacitor cells were developed using freshwater algae biomass. In the first stage, supercapacitor electrodes were prepared by Co-doped Chlorella vulgaris (Chl-Co), and in the second stage, electrodes were prepared by Co-doped to H3PO4-washed Chlorella vulgaris (Chl-Co-H3PO4). 6 M KOH solution was used as the electrolyte. Electrochemical characterization results of the electrodes were obtained very close to the ideal supercapacitor characteristic. The capacitance values of the Chl-Co electrode were measured as 80 F/g for 1 A/g, but after the activation by H3PO4, the capacitance rose to 169.7 F/g for 1 A/g. The produced electrodes are promising for energy storage in terms of environmental pollution, cost, stability, and capacity.

In the present study, a Mn-supported catalyst material developed from Microcystis aeruginosa microalgae for hydrogen generation was tested as a supercapacitor electrode material for the first time. The catalyst material (MA-HCl-Mn) was examined for hydrogen generation through methanolysis of NaBH4, and it demonstrated good catalytic activity. Symmetric and asymmetric supercapacitor cells were prepared using MA-HCl-Mn as the electrode material. The electrochemical performance of the cells were evaluated by a two-electrode system using 2 M KOH as the electrolyte. The gravimetric capacitance of the symmetric and asymmetric cells found to be 40 F/g and 71 F/g, respectively. It was concluded that MA-HCl-Mn served as a sustainable, dual functional material showing a high catalytic activity for the hydrogen generation and a promising electrochemical performance as the supercapacitor electrode.

The rapid development of the industry, rapid population growth, and the increase in the number of modern vehicles used lead to excessive energy consumption. For the purpose of meeting this consumption, the majority of energy is produced as a result of the burning of fossil fuels, especially in underdeveloped countries due to the fact that renewable energy sources have not reached the technological maturity yet. In addition, fossil fuels are still used in factories and homes for heating purposes. As a result of the combustion of these fossil fuels, large amounts of toxic gases are emitted into the atmosphere, and these gases have negative effects on the environment and indirectly on living beings. In this study, a new method was proposed to eliminate toxic components of flue gases. No chemical additives or catalysts were used in this study. In the proposed method, the chemical decomposition of SO2, CO, nitrogen oxide (NOX) gases was simultaneously achieved by applying voltages at various frequencies to a specially designed dielectric barrier discharges (DBD) reactor, and in a controlled manner, the conversion of these gases to other various chemical products was carried out. In this study, it was found that a significant part of the gases could be easily separated with the help of DBD plasma without the need for any catalyst or other systems. According to the results, it was observed that the effect of high-frequency plasma charge bombardment was highly effective in the simultaneous decomposition of toxic gas compounds.

The effect of several parameters, such as different Co2+ ratios, burning temperatures, and burning times, was examined by using defatted spent coffee grounds (DSCG) as organic waste to obtain the most effective catalyst for producing hydrogen. Under optimum conditions, the most active catalyst/metal ratio was obtained by burning 50% Co (2+) at 400 degrees C for 90 min. To measure the time-dependent amounts of hydrogen, 0.1 g of DSCG-Co catalyst was dissolved in 10 mL of a methanol solution containing 0.25 g sodium borohydride (NaBH4) at 30 degrees C. The maximum hydrogen generation rate obtained from the methanolysis of NaBH4 at 30 and 60 degrees C was found to be 8749 and 17,283 mL min(-1) gcat(-1), respectively, and the activation energy of the catalyst was found to be 23.2 kJ mol(-1). FTIR, ICP-OES, XRD, BET, and SEM-EDX analyses were performed for the characterization of the prepared DSCG-Co-Cat catalyst. Furthermore, a supercapacitor cell was constructed by using this catalyst as an active substance for electricity storage. The specific capacitance of the electrode at the current density of 1 A/g was calculated as 67 F/g for two-electrode systems. The results of electrochemical analysis of the prepared supercapacitor were found to be similar to the ideal supercapacitor curves. The obtained capacitance values are at very good levels in terms of the capacity and cost factors. The results indicated that the multifunctional capacitor-catalyst material produced by Co-doped waste coffee could constitute an important element in a hybrid system that includes capacitor and catalyst systems that can be installed in the future.

Currently, a novel green material, defatted spent coffee ground (DSCG), is employed as a support to prepare DSCG supported Ru (DSCG-Ru) material. DSCG and DSCG-Ru materials are characterized by advanced surface analytical techniques such as N-2 adsorption-desorption, X-ray diffraction, X-ray photoelectron spectroscopy, and H-2-temperature-programmed reduction. Characterization results revealed that DSCG-Ru was prepared successfully. First, DSCG-Ru is prepared at varying Ru contents on deoiled coffee waste and hydrogen production experiments are performed by the methanolysis of sodium borohydride on the DSCG-Ru catalysts. It is observed that optimum conditions for the catalyst preparation are examined on the 10% Ru containing DSCG-Ru catalysts and found as 10% Ru, 300 degrees C, and 60 minutes. DSCG catalyst containing 10% Ru completed the methanolysis reaction in 1.5 minutes. Capacitive measurements to investigate the supercapacitor property of DSCG-Ru catalysts prepared at optimum conditions 10% Ru, 300 degrees C, and 60 minutes is investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge measurements. Results revealed that gravimetric capacitance of the electrode at a current density is found as of 0.5 A/g and 43 F/g, greater than the literature values. DSCG-Ru, green novel supported Ru catalyst, has a dual promising performance in hydrogen production and supercapacitor measurements.

In this study, spent tea waste (STW) was utilized as an environmentally friendly, efficient, cost-effective, and SWT-H 3 PO 4 -Cat catalyst for the sodium boron hydride methanolysis process. Moreover, this synthesized catalyst was utilized as an active material of supercapacitor to store electricity and resulting in a material that served as a catalyst and a supercapacitor at the same time. The most active catalyst; It was obtained by carbonization for 40 minutes at 400 o C after treatment with 7M H 3 PO 4 . The synthesized catalyst's performance in the methanolysis reaction was investigated for hydrogen production. Afterwards, methanolysis processes were carried out at four various temperatures with the obtained SWT-H 3 PO 4 -Cat catalyst and reusability were tested. The FTIR, XRD, and SEM-EDX analyses were used to analyze the STW-H 3 PO 4 -Cat catalyst that showed the best catalytic activity. Consequently, the hydrogen generation rates (HGR) were found to be 52912 and 76640 mLmin -1 g.cat -1 for 30 o C and 60°C, respectively.

In recent years, there has been an increasing need for energy, depending on population growth and the rapid development of industry. Consequently, in large power plants, factories, and vehicles, large quantities of toxic gases are emitted into the air as a result of the burning of fossil fuels every year. These gases have negative effects on both human health and the environment. In this study, a new method was proposed for eliminating environmentally hazardous flue gases without the need of any chemical catalyst unlike existing methods. In the proposed method, chemical decomposition of toxic gases was achieved by applying voltages at various frequencies to a specially designed cylindrical and coaxial dielectric barrier discharges (DBD) reactor, and in a controlled manner, the conversion of these gases to other products which could be useful was carried out. In the study, it was found that most of the gases could be separated by DBD plasma, while some of them had to be subjected to a strong preheating process in order to be separated. According to the results, high frequency plasma charge bombardment has been shown to be highly effective in the decomposition of toxic gas compounds when used together with induction heating method.

Bu calismada, ilk once tek kutuplu bir Yuksek Gerilimli Dogru Akim (YGDA) iletim sistemi modeli olusturulmustur. Bu YGDA iletim sisteminde donusturuculerden kaynaklanan harmonikleri bastirmak icin seri, paralel ve seri-paralel aktif dogru akim filtre tasarimlari gerceklestirilmistir. Tasarlanan bu filtrelerin kullanildigi YGDA iletim sisteminin simulasyonlari MATLAB Simulink’te gerceklestirilmistir. Bu iletim sistemi modelinde filtresiz ve filtreli durumlar icin yuk akiminin ve geriliminin dalga sekilleri ile toplam harmonik distorsiyonu (THD) degerleri elde edilmistir. YGDA iletim sisteminde kullanilan aktif dogru akim filtreleriyle yuk gerilimindeki ve akimindaki harmonikler buyuk oranda bastirilmistir. Ayrica bu akim ve gerilimler icin THD degerleri %5’in oldukca altinda elde edilmistir. Bu sonuclara gore, tasarlanan aktif dogru akim filtrelerinin basit bir yapiya sahip olmasi ve kontrolunun fazla karmasik olmamasi onemli avantajlar saglamaktadir.