A Novel Co ₃ O ₄ @Co ₃ (HITP) ₂ ‐Based Sensor for Low‐Temperatures H ₂ S Detection: Fabrication, Performance, and Preliminary Exploration in Monitoring Pork Spoilage

ABSTRACT 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 Co 3 O 4 @Co 3 (HITP) 2 chemiresistor for hydrogen sulfide (H 2 S) sensing. The decoration of Co 3 (HITP) 2 with Co 3 O 4 nanoparticles facilitates carrier transfer and lowers the activation energy for H 2 S reaction. The optimized sensor demonstrates notable sensitivity, with response values ( R g /R a ) of 3.0 and 1.4 toward 10 ppm H 2 S at 25°C and 40°C, respectively. The excellent low‐temperature performance is primarily attributed to the Co 3 (HITP) 2 . As a proof‐of‐concept, a portable device with a smartphone interface was employed to monitor H 2 S released from pork spoilage at both temperatures. It is important to note that early spoilage involves complex volatile profiles, and sole reliance on H 2 S 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.