Deuterium has numerous applications in industry and scientific research. However, the conventional methods for separation hydrogen isotopes face the problems of low selectivity and high energy consumption. Recently, microporous material adsorption separation technology provides an efficient way for the separation of hydrogen isotopes. Herein, we prepared the metal bistriazolate framework Ni(2)Cl(2)BBTA, featuring a high density of coordinatively unsaturated Ni2+ sites. Interactions between the open metal sites and hydrogen render this material excellent separation ability for the capture of D-2 from the hydrogen isotopes mixture, with the D-2 over H-2 selectivity up to 4.5 at 77 K and 4.0 at 87 K respectively. Notably, recycle experiments show that this material has great potential in the application of hydrogen isotope separation, owing to its good structural stability and reusability. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.