Synthesis of group IA alkali metal-aluminosilicates, and their hydrogen production abilities on methanol thermal decomposition

• Published in: Energy (Oxford) Vol. 36; no. 5; pp. 3293 - 3301
• Main Authors: Lee, Juhyun, Lee, Jun Su, Kang, Misook
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.05.2011; Elsevier
• Subjects: Alternative fuels. Production and utilization; aluminum; Applied sciences; carbon; carbon dioxide; Carbon nano-filament; Catalysis; Catalysts; Catalysts: preparations and properties; catalytic activity; cesium; Chemistry; Energy; ethanol; Ethyl alcohol; Exact sciences and technology; Fuels; General and physical chemistry; hydrogen; Hydrogen production; IA–AlxSiyOz; methanol; Methanol thermal decomposition; Methyl alcohol; Nanostructure; potassium; scanning electron microscopy; silica; sodium; temperature; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Thermal decomposition; thermal degradation; Carbon nano-filament; IA–AlxSiyOz; Hydrogen production; Methanol thermal decomposition; Hydrothermal growth; Catalytic reaction; Thermal decomposition; Aluminosilicates; Alkali metal compound; Catalyst; Methanol
• ISSN: 0360-5442
• DOI: 10.1016/j.energy.2011.03.025

This work investigates the hydrogen generation via methanol thermal decomposition (TD) over the three group IA alkali metals, Na, K, and Cs, incorporated into aluminosilicate catalysts (IA–AlxSiyOz). The scanning electron microscopy (SEM) images of the IA–AlxSiyOz catalysts revealed various and regular morphologies such as cube (Na), bouquet (K), and spherical (Cs), but the other two catalysts, K-alumina and silica, were irregular and non-uniform. The catalytic performances differed according to the alkali elements. The K–AlxSiyOz catalyst provided a significantly higher methanol decomposition and hydrogen production than the other catalysts: the H 2 production was maximized at 78% at a reaction temperature of 550 °C, CH 3OH concentration of 30 vol-%, and gas hourly space velocity (GHSV) of 1800 h −1. In an unusual result, carbon nano filaments were created over the K–AlxSiyOz catalyst after the reaction even though CO 2 and ethanol were not used. In the proposed mechanism, the group IA metals played an important role in depressing the strong acidities at the Al sites, and K was determined to be the most effective in increasing the hydrogen yield and suppressing the generation of CO and CO 2. ► The K–AlxSiyOz catalyst provided a significantly higher methanol decomposition and hydrogen production than the other catalysts. ► The H 2 production in K–AlxSiyOz catalyst was maximized at 78% at a reaction temperature of 550 °C. ► Carbon nano filaments were created over the K–AlxSiyOz catalyst after the reaction. ► K was determined to be the most effective in increasing the hydrogen yield and suppressing the generation of CO and CO 2.