Embedded nano spin sensor for in situ probing of gas adsorption inside porous organic frameworks.

Spin-based sensors have attracted considerable attention owing to their high sensitivities. Herein, we developed a metallofullerene-based nano spin sensor to probe gas adsorption within porous organic frameworks. For this, spin-active metallofullerene, Sc 3 C 2 @C 80, was selected and embedded into a nanopore of a pyrene-based covalent organic framework (Py-COF). Electron paramagnetic resonance (EPR) spectroscopy recorded the EPR signals of Sc 3 C 2 @C 80 within Py-COF after adsorbing N 2 , CO, CH 4 , CO 2 , C 3 H 6 , and C 3 H 8 . Results indicated that the regularly changing EPR signals of embedded Sc 3 C 2 @C 80 were associated with the gas adsorption performance of Py-COF. In contrast to traditional adsorption isotherm measurements, this implantable nano spin sensor could probe gas adsorption and desorption with in situ, real-time monitoring. The proposed nano spin sensor was also employed to probe the gas adsorption performance of a metal-organic framework (MOF-177), demonstrating its versatility. The nano spin sensor is thus applicable for quantum sensing and precision measurements.