Preparation of chromium barium oxide catalysts for hydrogen evolution from sodium borohydride methanolysis

Abstract

This paper describes the synthesis of Cr2O3, Cr1.7Ba0.3O3, and Cr1.4Ba0.6O3 nanoparticles as catalysts to enhance hydrogen evolution in sodium borohydride methanolysis. Various characterization techniques, comprising X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and others were utilized to characterize the prepared nanoparticles. The XRD analysis showed that the formed Cr2O3 exhibits a hexagonal crystal structure, with an estimated mean crystallite size of 24 nm. SEM micrographs showed nanoparticles with homogeneous distributions, exhibiting spherical or distorted spherical shapes. XPS analysis showed that all synthetic Cr2-xBaxO3 materials consist of Cr, O, and the presence of Ba for doped samples. The energy gap for pure Cr2O3 nanoparticles was determined to be 3.28 eV. Inclusion of Ba into the Cr2O3 nanostructure modified the band gap, resulting in values of 2.8 and 1.5 eV at 15 % and 30 % barium content. The hydrogen production rate from NaBH4 methanolysis for Cr2O3, Cr1.7Ba0.3O3, and Cr1.4Ba0.6O3 catalysts were 5984, 31176 and 11913 mL/g.min, respectively.