Fig. 1

1H NMR spectra of hydrogen gas in the stacking interstices of silica microsphere samples with different particle sizes: (a)~(d) correspond to the spectra of hydrogen gas in silica microspheres with particle sizes of 100 μm, 10 μm, 5 μm, and 100 nm, respectively; (e) shows the spectrum of hydrogen gas in a porous silica sample with an average pore size of 3 nm; (f) scanning electron microscope (SEM) image of silica microspheres with a diameter of 100 μm

Fig. 2

1H NMR spectra and schematic diagrams of three control samples. (a) Spectrum of Sample 1; (b) spectrum of Sample 2; (c) spectrum of Sample 3; (d)~(f) schematic diagrams of Sample 1, 2, and 3, respectively, where the black shading represents added silica dioxide

Fig. 3

2D 1H exchange spectrum of hydrogen gas molecules of Sample 3 at different mixing time

Fig. 4

The experimental results of the self-diffusion coefficient determination for Sample 3: (a)~(c) correspond to the diffusion spectra of hydrogen gas under diffusion gradient strengths of 2%, 7%, and 10%, respectively; (d) the relationship between the ln(I/I0) signal intensity of two types of hydrogen molecules (inside and outside the nano pores) and (gγδ)2(Δ-δ/3). The term 'in-pore' in the figure refers to the signal intensity of hydrogen molecules inside the pores, while 'ex-pore' refers to the signal intensity of hydrogen molecules outside the pores

Fig. 5

The variable temperature 1H NMR experimental results of hydrogen gas in nanoporous silica sample. (a) 1H spectrum of hydrogen gas at different temperatures; (b) the correlation between the half-width of the hydrogen signal and temperature