A Novel Co3O4@Co3(HITP)2-Based Sensor for Low-Temperatures H2S Detection: Fabrication, Performance, and Preliminary Exploration in Monitoring Pork Spoilage.

Conductive metal-organic frameworks (cMOFs) are promising for room-temperature gas sensing, yet their development for highly sensitive detection at refrigeration temperature remains a challenge. This work addresses this gap by developing a heterostructured Co3O4@Co3(HITP)2 chemiresistor for hydrogen sulfide (H2S) sensing. The decoration of Co3(HITP)2 with Co3O4 nanoparticles facilitates carrier transfer and lowers the activation energy for H2S reaction. The optimized sensor demonstrates notable sensitivity, with response values (Rg/Ra) of 3.0 and 1.4 toward 10 ppm H2S at 25°C and 40°C, respectively. The excellent low-temperature performance is primarily attributed to the Co3(HITP)2. As a proof-of-concept, a portable device with a smartphone interface was employed to monitor H2S released from pork spoilage at both temperatures. It is important to note that early spoilage involves complex volatile profiles, and sole reliance on H2S detection may be limited due to potential temporal mismatches with other key spoilage markers. This study presents a functionalization strategy to extend cMOF-based sensing into lower temperature regimes, offering a material platform for chilled meat safety monitoring while acknowledging the constraints of single-analyte detection for early warning.