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.