Synthesis and electrochemical properties of mesoporous La_1−xMg_xAlO_3−δ nanopowders by sol-gel method

ABSTRACT

In this work, oxides mesoporous La_1−xMg_xAlO_3−δ (0 ≤ x ≤ 0.15) nanopowders were synthesized by sol-gel method. The properties of these powders were characterized with several analytical techniques including thermogravimetric and differential thermal analysis, X-ray diffractometry, infrared spectroscopy, scanning electron microscopy, Brunauer–Emmett–Teller analysis, and Barrett–Joyner–Halenda analysis. After the precursor was further calcined at 800°C for 6 h in air, a single-phase perovskite, La_1−xMg_xAlO_3−δ (0 ≤ x ≤ 0.15), was formed without any traceable impurities based on XRD diffraction analysis. Surface areas, pore diameters, and crystallite sizes are in the 12.9–20 m² g⁻¹, 8.8–11.28 and 25.4–30.5 nm ranges, respectively. Taking into consideration the possible application of these compounds as catalysts in direct methanol fuel cells, their catalytic properties toward oxidation of methanol in the basic solutions were studied by cyclic voltammetry. La_0.85Mg_0.15AlO₃ modified electrodes responded extremely well to methanol by giving high anodic current for methanol oxidation.

KEYWORDS:

• Mesoporous LaAlO₃
• perovskite
• sol-gel method
• specific surface area
• electocatalytic properties