Fig. 1: Probing the gas adsorption performance of Py-COF using the molecular spin of Sc₃C₂@C₈₀.

a Schematic of the nano spin sensor in a Py-COF channel. b Structure and spin density distributions of Sc₃C₂@C₈₀. c Theoretically computed unit structure of Sc₃C₂@C₈₀⊂Py-COF. d Powder X-ray diffraction (PXRD) patterns of Py-COF (Blue) and Sc₃C₂@C₈₀⊂Py-COF (Orange). The insets present the sample pictures of Py-COF and Sc₃C₂@C₈₀⊂Py-COF. e Sketch of the experimental setup, which allows vacuuming, inflation, and EPR measurements of Sc₃C₂@C₈₀⊂Py-COF in a quartz tube. Figure created with BioRender.com. f EPR spectra of Sc₃C₂@C₈₀⊂Py-COF under vacuum and after N₂, CO, CH₄, CO₂, C₃H₈, and C₃H₆ adsorption. g Integrated EPR spectra of Sc₃C₂@C₈₀⊂Py-COF under different conditions. h Difference values between the integrated EPR signal area of Sc₃C₂@C₈₀⊂Py-COF after adsorbing one gas and the counterpart of Sc₃C₂@C₈₀⊂Py-COF under vacuum conditions. Source data are provided as a Source Data file.