Enhanced sorption performance of MgH2 doped with reduced metal-organic framework of Ni-Co-MOF-74

Abstract

Improvement has been made in hydrogen storage performance particularly in MgH2 system prepared via high energy ball milling technique where bi-metal in the metal organic framework of Ni-Co-MOF-74 was introduced as catalyst. Better catalytic effect was recorded when pre-reduced Ni-Co-MOF-74 is used as catalyst for both hydrogen absorption and desorption. An apparent amount of reduced metal species in the MgH2 system containing bi-metal in metal organic framework promotes more active sites which eventually improved the sorption properties and shifted the thermodynamic stability of the composite. At 280°C, hydrogen desorption was 4.7 wt% in a period of 30 minutes whereas at 200°C a remarkable hydrogen amount of 6.3 wt% was stored in 2 minutes. It is believed that the distinctive coordinate of the metal in the pre-reduced metal organic framework improved the dispersion of the catalyst thus enriched the sorption properties.