Study on the hydrogen storage property of two-dimensional layered MXene material Nb2 C catalytically modified Mg(BH4)2
Magnesium borohydride is considered to be a promising high-capacity hydrogen storage material due to its hydrogen storage capacity of 14.9％.Considering that transition metal carbides have a significant catalytic effect on the hydrogen evolution process of Mg(BH4)2,acid etching method was used to prepare MXene material Nb2C microscopically characterized as two-dimensional layers,and the niobium carbide(Nb2C)was prepared by mechanical ball milling.The as-prepared Nb2C was doped into Mg(BH4)2 by the method to catalyze the modifi-cation of the hydrogen release properties of Mg(BH4)2.It can be obtained from the programmed temperature de-sorption(TPD)test:in the catalytic modification system of Mg(BH4)2-x％Nb2C(x=20,30,40),when x= 40,the initial hydrogen desorption temperature of the Mg(BH4)2-40％Nb2C system can be reduced to about 130℃,and 12.8％H2 can be released after heating to 500℃.Nevertheless,the pristine Mg(BH4)2 without Nb2C addition starts to release hydrogen at about 285℃.Furthermore,the isothermal hydrogen desorption test also showed favorable dehydrogenation kinetics.Moreover,the kinetic performance of hydrogen desorption modi-fied by this system can be retained in the subsequent second and third hydrogen absorption and desorption cy-cles,showing excellent cycle performance.
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