“…The first of these novel mechanisms is kinetic quantum sieving (KQS): D 2 , which has a shorter de Broglie wavelength than H 2 , can diffuse faster through confined pores under cryogenic conditions. The second mechanism is chemical affinity quantum sieving (CAQS): D 2 , which has a lower zero-point energy than H 2 , can adsorb preferentially through the strong sorption sites inside crystalline porous materials. − Subsequently, H 2 /D 2 separation techniques utilizing precisely controlled aperture sizes, , local flexibility of apertures, the gating effect of dynamic pore opening, breathing transitions, binding strengths, ,, or two of these properties taken together have led to promising observations. The studies mentioned so far have separated D 2 and H 2 using the minor differences in boiling point, diffusion rate (KQS), and substrate interaction energy (CAQS) rather than utilizing molecular recognition.…”