Orhan Baytar

Hydrogen Generation from NaBH4 Solution with the High-performance Co(0) Catalyst Using a Cold Plasma Method

The hydrogen production from the hydrolysis of NaBH4 with Co(0) catalyst, which is prepared with a cold plasma method under nitrogen atmosphere, was investigated with effects of NaBH4 and NaOH concentration, temperature, plasma applying time and applying power, and Co(0) catalyst effect. The hydrolysis reaction completed within around 10-min time intervals with cold plasma, while the hydrolysis reaction in the known method completed within around 20-min time intervals. The completion rate of hydrolysis reaction with Co(0) catalyst in cold plasma media compared to non-plasma media increased to be around 100%. The yield of hydrogen in the presence of 3.2, 10, and 25% NaBH4 solution takes the values of around 94, 90, and 15% at the end of 600 sec, respectively. The experimental data were fitted to first-order. The activation energy for first-order was found to be 26.02 kJ mol−1.

Hydrogen Generation from Hydrolysis of Sodium Borohydride with Ni(0) Catalyst in Dielectric Barrier Discharge Method

In this study, the hydrogen production from hydrolysis of sodium borohydride (NaBH4) in the presence of the catalytic properties of Ni(0), which is reduced from NiCl2.6H2O, was investigated with a dielectric barrier discharge plasma method. The hydrogen production from NaBH4 hydrolysis with Ni(0) catalyst prepared in dielectric barrier discharge plasma media created by applying a certain amount of voltages (3–5 kV) and plasma applying times (5–15 min) was investigated depending on NaBH4 concentration (3.2–10%) in solutions, NaOH concentration (1.5–10%) in solutions, catalyst amount (5–20 mg), and temperature (20–60°C). Hydrolysis reaction of NaBH4 with Ni(0) prepared in the presence of dielectric barrier discharge plasma is completed in 45-min time intervals with fast hydrogen generation while the Ni(0) produced in a known method led to a slow hydrogen release and hydrolysis is completed in 70-min time intervals. The hydrogen yield of 3.2, 5, and 10% NaBH4 solution with Ni(0) catalyst prepared in the presence of dielectric barrier discharge plasma takes the values of 95.06, 57.42, and 31.78% at the end of 45 min, respectively. The experimental data were fitted to first-order. The activation energy for first-order was found to be 41.76 kJ mol−1.

Synthesis, structural, optical and photocatalytic properties of Fe-alloyed CdZnS nanoparticles

In this study, Fe-alloyed CdZnS nanoparticles (NPs) with 1% Fe concentration (Fe (1%): CdZn (2%)S) were synthesized by chemical precipitation at room temperature. The synthesized NPs were used as a catalyst for the decomposition of methylene blue under UV light. The obtained results showed that the photocatalytic activity of Fe (1%): CdZn (2%)S NPs was higher than that of CdZn (2%)S NPs. It was determined that the kinetics of the photocatalytic degradation of the methylene blue (MB) correspond to the pseudo-second order kinetics model. In addition to the photocatalytic properties, the structural, morphological and optical properties of Fe (1%): CdZn (2%)S NPs were investigated.

Photocatalytic degradation of methylene blue with Co alloyed CdZnS nanoparticles

In our present study, firstly; cadmium zinc sulfide (CdZnS) nanoparticles (NPs) with 1, 2, 5, 10% of Zn concentration were synthesized in aqueous solution by simple chemical co-precipitation method and their photocatalytic activity was investigated using the degradation of methylene blue under visible light in air at room temperature. It was found that CdZnS NPs with 2% of Zn concentration indicates the highest degradation efficiency compare to other Zn concentrations. CdZnS NPs with 2% of Zn concentration was symbolized as CdZnS_1. Later; 0.1, 0.2, 0.5, 1, 5, 10% of cobalt (Co) concentration was separately alloyed on the CdZnS_1 NPs. It was oberved that Co(5%):CdZnS NPs has the highest degradation efficiency. Structure, surface morphology, elemental analysis and optical properties of CdZnS_1 and Co (5%): CdZnS NPs 0were analyzed using X-ray diffraction (XRD), scanning electron microscopy, energy dispersive X-ray and UV–Vis absorption measurements, respectively. The results showed that Co doped CdZnS NPs can be employed as capable materials to ehance the photocatalytic activity.

Characterization of Microwave and Conventional Heating on the Pyrolysis of Pistachio Shells for the Adsorption of Methylene Blue and Iodine

ABSTRACT The production of activated carbon was investigated using the sequential combination of microwave and conventional heating of pistachio shells as the raw precursor with zinc chloride. Several techniques such as thermogravimetric and differential thermal analyses, infrared spectroscopy, scanning electron microscopy, and specific surface area analyses were performed to characterize the samples. The highest specific surface area value for the activated carbon prepared at a microwave power of 200 W with microwave time of 20 min, and flow rate of 50 mL min−1 was 1468 m2 g−1. The methylene blue and iodine adsorption capacities were 331 and 1276 mg g−1, respectively. The results were compared to those obtained using physical and chemical activation methods and showed that the sequential combination of microwave and conventional heating reasonably influenced the micropore surface area of the samples as well as the specific surface area.

Preparation and Characterization of Activated Carbon from Sesame Seed Shells by Microwave and Conventional Heating with Zinc Chloride Activation

ABSTRACT The preparation of activated carbon from sesame shells as raw precursor was investigated in the study by sequentially applying microwave and conventional heating methods assisted by zinc chloride activation. The optimizisation of experimental parameters including microwave power, microwave treatment time, conventional activation time, conventional activation temperature and zinc chloride concentration ratio for the microwave and conventional heating method was performed. The characterization of the prepared activated carbon was done by thermogravimetric and differential thermal measurements, infrared spectroscopy, scanning electron microscopy and specific surface area analyses. The maximum surface area of 1254 m2/g for the prepared activated carbon was obtained at a microwave power of 750 W, a microwave treatment time of 20 min, an activation time of 45 min, an activation temperature of 500°C and zinc chloride concentration ratio of 1:1. Methylene blue and iodine adsorption capacities for the prepared activated carbon were 103 and 1199 mg/g, respectively.

Preparation and Characterization of Activated Carbon from Microwave and Conventional Heated Almond Shells Using Phosphoric Acid Activation

Abstract Activated carbon production from almond shells using phosphoric acid activation agent was achieved by applying both conventional heating and microwave heating in succession. The morphology and surface properties of activated carbon were studied using thermogravimetric and differential gravimetric analysis, Fourier-transform infrared spectroscopy, scanning electron microscopy, and Brunauer–Emmett–Teller analysis. A surface area of 1128 m2/g was achieved by optimizing the microwave power (500 W), microwave application time (15 minutes), conventional heating time (45 minutes), conventional heating temperature (500 °C), and the phosphoric acid:sample ratio (0.7:1). An adsorption capacity of methylene blue of 148 mg/g and an iodine value of 791 mg/g was obtained for the prepared activated carbon.

Investigation of high-activity activated carbon-supported Co-Cr-B catalyst in the generation of hydrogen from hydrolysis of sodium borohydride

In this study, activated carbon-supported Co-Cr-B catalyst was synthesized by chemical impregnation and precipitation method for use in the catalytic hydrolysis of sodium borohydride (NaBH4). The activity of Co-Cr-B / activated carbon (5-20%) obtained by using different ratios was investigated while synthesizing activated carbon-supported Co-Cr-B catalyst. The effects of some parameters such as NaOH Concentration (0-5%), NaBH4 concentration (2.5-10%), amount of catalyst (25-100 mg) and solution ambient temperature were investigated in the catalytic hydrolysis of NaBH4. The hydrogen production rate of Co-Cr-B catalyst without support in hydrolysis of NaBH4 was found as 6.5 Lg-1 min-1 catalyst while the hydrogen production rate of activated carbon supported Co-Cr-B catalyst was found as 30.2 Lg-1 min-1 catalyst. In presence of activated carbon-supported Co-Cr-B catalyst, the hdyrolysis kinetic order and activation energy of NaBH4 were found as 0.126 and 16.27 kJ/mol, respectively. The results suggest that activated carbon-supported Co-Cr-B catalysts can be used for mobile applications of Proton exchange membrane fuel cell (PEMFCs) systems.