Yazar "Buyukkanber, Kaan" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • [ X ]
    Öğe
    High catalytic activity of cobalt nanoparticles synthesized by ultrasonic spray method in sodium borohydride hydrolysis
    (Pergamon-Elsevier Science Ltd, 2024) Buyukkanber, Kaan; Ekinci, Arzu; Sahin, Omer
    Enhancing the hydrolysis reaction of NaBH4 for efficient hydrogen production requires the development of effective catalysts. In this study, the solution particles used for nanoparticles synthesized using the ultrasonic spray (US) method were produced for the first time in N2 at room temperature in the gas and liquid intermediate phases. It also brings a new approach to synthesizing low-cost and efficient catalysts using ultrasonic spray technology. The proposed method involves US the CoCl2 solution into the NaBH4 solution to reduce cobalt, producing catalysts for hydrogenation. This innovative approach pioneers a gas-liquid interface reaction for metal reduction. The resulting catalysts were characterized using SEM, XRD, XPS, TEM, BET and FT-IR analysis. The influence of NaOH/NaBH4 concentration, solution temperature, and catalyst amount on hydrogen production rate was investigated, and kinetic parameters were analyzed to understand the reaction kinetics better. The hydrogen production rates of US-Co and reduction method (RM) Co catalysts under the same conditions were calculated as 3995 mlH2/min.gcat and 1245 mlH2/min.gcat, respectively. The activation energy values calculated for the NaBH4 hydrolysis of the US-Co catalyst using the nth-order and Langmuir-Hinshelwood kinetic models are 46.75 kJ/mol and 46.87 kJ/mol, respectively. Therefore, it can be concluded that the LangmuirHinshelwood kinetic model is consistent with the nth-order kinetic model. Experimental results showed that the ultrasonic spray method is very effective in producing active metal catalysts, offering promising opportunities for catalytic advances.
  • [ X ]
    Öğe
    Improved catalytic activity in PdCo nanocatalysts synthesized via ultrasonic spray method for PEMFC applications
    (Pergamon-Elsevier Science Ltd, 2024) Ekinci, Arzu; Buyukkanber, Kaan; Akdag, Abdurrahman; Sahin, Ohmer
    The current emphasis of research on PEM fuel cells is the exploration of novel, resilient, and very efficient electrocatalysts that do not rely on platinum, while also ensuring long-term stability. This study aimed to enhance the catalytic activity as cathode electrocatalysts by synthesizing Palladium-cobalt alloy nanoparticles using the ultrasonic spraying (US) technique and then dispersing them over a carbon black substrate. The ultrasonic spray method produces crystalline catalysts in the liquid-vapor interface reaction without requiring additional energy. Analyses were performed using XRD, SEM, EDS, XPS and TEM to determine the structural and morphological properties of the nanocatalysts. XRD analysis determined the average particle size of USCo-Pd/C and US-CoPd/C nanocatalysts to 1.37 nm and 1.09 nm, respectively. CV measurements identified ECSA values for USCo-Pd/C and US-CoPd/C as 7.1 m(2)/gPd and 8.9 m(2)/gPd. The relative performance ranking of cathode electrocatalysts for PEM fuel cells was evaluated at a cell temperature of 70 C-degrees. The order of reactivity for the catalysts is as follows: US-CoPd/C > USCo-Pd/C > PdCo/C > Pd/C. The better electrochemical performance of USCo-Pd/C and US-CoPd/C nanocatalysts as cathode catalysts in PEM fuel cell applications, in comparison to Pd/C and PdCo/C catalysts, can be attributed to the modification of the electronic structure of palladium. This modification depends on the synthesis of cobalt and palladium metals together using the US method and the synergistic effect of the catalysts.