Abstract
Mg (MgH2)-based composites, using carbon nanotubes (CNTs) and pre-synthesized vanadium-based complex (VCat) as the catalysts, were prepared by high-energy ball milling technique. The synergistic effect of coupling CNTs and VCat in MgH2 was observed for an ultra-fast absorption rate of 6.50 wt. % of hydrogen per minute and 6.50 wt. % of hydrogen release in 10 min at 200 °C and 300 °C, respectively. The temperature programmed desorption (TPD) results reveal that coupling VCat and CNTs reduces both peak and onset temperatures by more than 60 °C and 114 °C, respectively. In addition, the presence of both VCat and CNTs reduces the enthalpy and entropy of desorption of about 7 kJ/mol H2 and 11 J/mol H2·K, respectively, as compared to those of the commercial MgH2, which ascribe to the decrease of desorption temperature. From the study of the effect of CNTs milling time, it is shown that partially destroyed CNTs (shorter milling time) are better to enhance the hydrogen sorption performance.
Highlights
One of the challenges that need to be addressed for materializing zero-emission in mobile application is the mode of energy storage
In our previous work [17], we reported that the synergistic effect of combining individual metal nanoparticles (Fe and Ti) and carbon nanotubes (CNTs) on the kinetics as well as in hydrogen storage capacity
The amount of additives introduced to MgH2 was 5 wt. % each and the ball to powder ratio was kept at 40:1 in all samples. Another sample was prepared with shorter CNTs milling time, in which CNTs were introduced to MgH2 + vanadium-based complex catalyst (VCat) after a 4.5 h milling period to give only 0.5 h of CNTs milling time; this sample is denoted as MV(4.5)cnt(0.5)
Summary
One of the challenges that need to be addressed for materializing zero-emission in mobile application is the mode of energy storage. Most reported investigations require long milling times ranging between 10 to 80 h [16,21,22] in preparation of a storage material with reasonable sorption performance. This is obviously not economical when considering mass production. The hydrogen sorption of magnesium hydride composites containing both vanadium-based complex catalyst and CNTs were investigated. The in situ formed metallic particles of VCat are all at nanoscale possibly reduce the sample milling time while maintaining high hydrogen storage performance. The function of CNTs was identified by investigating the effect of CNTs milling time on hydrogen storage of the composites
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
