Carbon monoxide gas sensor based on Co/Ni-MOF-74 coated no-core-fiber Michelson interferometer

A Michelson interferometric carbon monoxide (CO) fiber-optic sensor based on Co/Ni-MOF-74 is proposed and fabricated. The bimetallic-ion-coordination MOFs material Co/Ni-MOF-74 was prepared by solvothermal method. Through XRD and XPS characterizations, the results show that Co/Ni-MOF-74 and Ni-MOF-74 have the same crystal structure. Co/Ni-MOF-74 has a good adsorption effect on CO, and it is integrated into the optical fiber sensing structure for CO detection. In the CO concentration range of 0–35 ppm, the sensitivity and linearity are 0.022 35 dB/ppm and 0.999 36, respectively. The detection limit of the sensor is about 1.990 46 ppm. The presented fiber-optic sensor has excellent selectivity, resistance to temperature interference and good time stability, and it is expected to be applied to the detection of trace CO.