Ppb-level H2S gas sensor based on CuNi-MOFs derivatives for meat freshness detection at low temperature environment

Abstract

H2S is usually used as one of the landmark gases for meat freshness detection under low temperature storage conditions. In this paper, the NiO-doped CuO composite derived from MOFs was synthesized by a low temperature (−25 ℃) precursor hydrothermal and sintering procedure for H2S detection. The influence of precursor solution temperature and sintering temperature on the structure of MOFs derivatives were discussed by SEM, TEM, and XRD characterization. The hydrothermal method of low-temperature precursor has guiding significance in improving the gas response performance of MOFs/MOFs derivatives. The sensor based on NiO-doped CuO composites derived from MOFs exhibited a ppb-level response to H2S gas. The sensor response is 106 % to 50 ppb H2S. Meanwhile, the sensor has good selectivity, and the response and recovery time are 115 s and 251 s, respectively. The low temperature precursor hydrothermal method directly affected the morphology and structure of MOFs derivatives by regulating the kinetics for MOFs nucleation and crystal growth, obtains more active adsorption sites. In addition, the composite has good sensing performance for H2S at the ambient temperature of 4 ℃ and −18 ℃, which verified the effectiveness for the detection of meat spoilage under a low temperature storage. Furthermore, the sensor based on NiO-doped CuO composites is a good candidate for H2S gas detection in meat freshness evaluation. Finally, an integrated circuit detection system was designed to detect H2S gas at different ambient temperatures. This work provides a new idea for meat freshness detection in a cold storage environment.