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

This paper describes the synthesis of Cr₂O₃, Cr_1.7Ba_0.3O₃, and Cr_1.4Ba_0.6O₃ 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 Cr_2-xBa_xO₃ 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, Cr_1.7Ba_0.3O₃, and Cr_1.4Ba_0.6O₃ catalysts were 5984, 31176 and 11913 mL/g.min, respectively.