# Influence of Structural Determinants on Dihydrogen Adsorption and Isotopologue Separation in Nanoporous Metal–Organic Frameworks

## TL;DR

This paper explores how the structure of metal-organic frameworks (MOFs) affects their ability to separate hydrogen isotopes, which is important for nuclear and environmental applications.

## Contribution

The study introduces new MOF materials with high selectivity for D2/H2 separation through structural design.

## Key findings

- Ultramicroporous MOFs enable D2 adsorption via kinetic quantum sieving.
- Ni-MOF-74(Co) achieves high selectivity (S = 52) through chemical affinity quantum sieving.
- Flexible MOFs show temperature-responsive selectivity for D2/H2 separation.

## Abstract

Efficient separation
of dihydrogen isotopologues, particularly
D2, is critical for applications in nuclear energy technology
and environmental sciences. Conventional methods, such as cryogenic
distillation, are energy-intensive and provide limited selectivity
(S ≈ 1.4). Here, we report a systematic evaluation of diverse
MOFs with ultramicropores, open metal sites (OMS), and framework flexibility
for D2/H2 separation. Thermal desorption spectroscopy
(TDS) and adsorption studies revealed that ultramicroporous MOFs enable
preferential D2 adsorption via kinetic quantum sieving,
while bimetallic Ni-MOF-74­(Co) achieves high selectivity (S = 52 at
77 K) through OMS-driven chemical affinity quantum sieving. Flexible
MOFs, [Cu2(nPr-trz-ia)2] and [Cu2(Et-trz-ia)2], show temperature-responsive cryogenic
flexibility with selectivities of 1.4–2.3 at 77 K. These findings
highlight structural design as the key to advancing dihydrogen isotopologue
separation at practical temperatures.