Nuclear Magnetic Resonance Characterization of Porous Materials

Nuclear magnetic resonance (NMR) provides a non-destructive window into the architecture and internal dynamics of porous solids and the fluids they contain. By measuring the relaxation behaviour and diffusion of nuclear spins—most commonly of hydrogen nuclei in water or probe molecules—one can infer pore size distributions, connectivity, surface interactions and transport rates. Relaxation times (T₁ and T₂) reflect molecular motion and interactions with pore walls, while pulsed-field-gradient NMR yields self-diffusion coefficients that probe tortuosity and pore network geometry. Cryoporometry exploits shifts in phase transitions of confined liquids to map pore volumes across nano- to meso-scales. Fast-field-cycling relaxometry extends this capability by varying the magnetic field to sample molecular motions over a broad timescale. Combined with complementary techniques such as density functional theory calculations and imaging methods, NMR characterisation underpins advances in catalysis, energy storage, groundwater science, carbon capture and advanced materials design.

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Nuclear Magnetic Resonance Characterization of Porous Materials publication trend

The graph below shows the total number of articles in nuclear magnetic resonance characterization of porous materials across all publications each year (not limited to Nature Index journals).

Technical terms

NMR relaxometry: Measurement of nuclear spin-lattice (T₁) and spin-spin (T₂) relaxation times to probe molecular mobility and surface interactions within porous materials.

T₁ relaxation time: Time constant governing the return of nuclear spin populations to thermal equilibrium with the lattice; sensitive to molecular motions at frequencies near the Larmor frequency.

T₂ relaxation time: Time constant describing the decay of transverse spin coherence; influenced by local magnetic inhomogeneities and interactions with pore surfaces.

Fast-field-cycling (FFC) NMR: Technique that varies the magnetic field during measurement to sample relaxation rates over a range of frequencies, revealing molecular dynamics across multiple timescales.

Cryoporometry: Method using melting and freezing point shifts of confined liquids to derive pore volume and size distribution.

References

1. Robust Algorithms for the Analysis of Fast-Field-Cycling Nuclear Magnetic Resonance Dispersion Curves. Computers (2024).
2. Adsorbate/adsorbent interactions in microporous zeolites: mechanistic insights from NMR relaxation and DFT calculations. Materials Today Chemistry (2023).
3. Interpretation of NMR Relaxation as a Tool for Characterising the Adsorption Strength of Liquids inside Porous Materials. Chemistry - A European Journal (2014).