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3. Study of the activity of a novel green catalyst used in the production of hydrogen from methanolysis of sodium borohydride

Author

Tülin Avci Hansu

Subjects
biology, Hydrogen, Chemistry, Metal-free catalyst,Microcystis aeruginosa,Methanolysis,NaBH4, Mühendislik, chemistry.chemical_element, biology.organism_classification, Catalysis, Sodium borohydride, chemistry.chemical_compound, Engineering, Automotive Engineering, Microcystis aeruginosa, Nuclear chemistry
Abstract

Biomass is an important energy source because it is easily accessible, contributes to the protection of the environment, and can be easily used in industry. Biomass resources can be classified as plants, vegetable and animal wastes, urban and industrial wastes. Highly active catalysts can be prepared by physical and chemical activation methods. Here, Microcystis aeruginosa was used as a biomass source and a metal-free catalyst was synthesized. The production conditions were determined by burning the microsistis modified with 3M H3PO4 at different temperatures (100, 200, 300 and 400 oC) and at different times (30, 45, 60 and 90 minutes). Parameters such as NaBH4 amount, catalyst amount and temperature of the synthesized MA- H3PO4 catalyst that affect methanolization were investigated. In the kinetic calculations, the reaction order was found as n 0.18, activation energy 19.014 kj / mol and initial rate 4998.7 ml H2min-1gcat-1. The reusability of the MA-H3PO4 catalyst was tested 5 times and its stability determined.

Published
2021

4. Carbon nanotube supported direct borohydride fuel cell anode catalysts: the effect of catalyst loading

Author

Aykut Caglar, Hilal Demir Kıvrak, Ömer Şahin, and Tulin Avcı Hansu

Subjects
pd/cnt, fuel cell, sodium borohydride, catalyst, Engineering (General). Civil engineering (General), TA1-2040
Abstract

At present, monometallic CNT supported Pd electrocatalysts (Pd/CNT) are prepared at varying Pd loadings via sodium borohydride (NaBH4) reduction method to investigate their NaBH4 electrooxidation activities. These monometallic Pd/CNT catalysts are characterized by X-ray Diffraction (XRD), N2 adsorption-desorption, Fourier-Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy-Energy Dispersive X-ray analysis (SEM-EDX). Characterization results are revealed that Pd/CNT metallic Pd with a face center cubic structure is detected. The crystallite size corresponding to (1 1 1 ) plane is found as 5.87 nm for 30% Pd/CNT catalyst. The average pore size, pore-volume, and Brunauer, Emmet ve Teller (BET) surface area of Pd/CNT are obtained as 24.5 nm, 0.93 cm³/g, and 129.48 cm2/g, respectively. From the SEM-EDX results, it indicates that the Pd metal is homogeneously distributed in the carbon structures. NaBH4 electrooxidation measurements are performed with cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). The effect of Pd loading (0.1-70.0 %) for NaBH4 electrooxidation is investigated via CV. The 30% Pd/CNT catalyst exhibits the highest electrochemical activity with a current density of 16.5 mA cm-2. By altering Pd loading, catalyst surface electronic structure changes significantly, leading to enhanced NaBH4 electrooxidation activity. CA and EIS measurement results are agreement with CV results. As a conclusion, it is clear that Pd/CNT catalysts are promising catalysts for direct borohydride fuel cells.

Published
2020

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