Hydrogen sorption enhancement by Nb2O5 and Nb catalysts combined with MgH2

• Published in: Journal of alloys and compounds Vol. 550; pp. 179 - 184
• Main Authors: da Conceição, M.O.T., Brum, M.C., dos Santos, D.S., Dias, M.L.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15-02-2013; Elsevier
• Subjects: Alternative fuels. Production and utilization; Applied sciences; Energy; Exact sciences and technology; Fuels; Hydrogen; Hydrogen absorbing materials; Mechanical alloying; Metal hydrides; Metal hydrides; Mechanical alloying; Hydrogen absorbing materials; Differential scanning calorimetry; Hydrogen storage; Heat treatment; Crystallization; Specific surface area; X ray diffraction; Composite material; Sorption; Magnesium hydride; Niobium oxide; Kinetics; Amorphous state structure; Catalyst
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2012.09.094

► The samples, MgH2+Nb catalysts, were obtained by mechanical milling. ► The synthesized, high surface area, Nb2O5 showed to be a promising material. ► A hydrogen capacity of 5.2wt.% was attained in 1.3min with MgH2+5wt.% s-Nb2O5.
Three Nb materials, synthesized oxide (s-Nb2O5), commercial oxide (c-Nb2O5) and metallic Nb, were applied as catalysts to promote the enhancement of hydrogen sorption in MgH2. A high specific surface area, around 100m2g−1, was obtained for both oxides used as catalysts, s-Nb2O5 and c-Nb2O5 after being heat treated at 350°C. X-ray diffraction (XRD) tests, performed prior to milling, revealed the amorphous structure of both oxides. All the catalysts were mixed for only 20min with MgH2 by mechanical milling forming composites. Differential Scanning Calorimetric curves of the s-Nb2O5 and c-Nb2O5 showed the presence of exothermic crystallization peaks. A total capacity of 5.8wt.% was attained when the hydrogen absorption kinetic tests were conducted at 350°C, with the MgH2+5wt.% s-Nb2O5 sample.