  Metal-organic frameworks (MOFs) are promising materials for gas sensing but
are often limited to single-use detection. We demonstrate a hybridization
strategy synergistically deploying conductive MOFs (cMOFs) and conductive
polymers (cPs) as two complementary mixed ionic-electronic conductors in
high-performing stand-alone chemiresistors. Our work presents significant
improvement in i) sensor recovery kinetics, ii) cycling stability, and iii)
dynamic range at room temperature. We demonstrate the effect of hybridization
across well-studied cMOFs based on 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP)
and 2,3,6,7,10,11-hexaiminotripphenylene (HITP) ligands with varied metal nodes
(Co, Cu, Ni). We conduct a comprehensive mechanistic study to relate energy
band alignments at the heterojunctions between the MOFs and the polymer with
sensing thermodynamics and binding kinetics. Our findings reveal that hole
enrichment of the cMOF component upon hybridization leads to selective
enhancement in desorption kinetics, enabling significantly improved sensor
recovery at room temperature, and thus long-term response retention. This
mechanism was further supported by density functional theory calculations on
sorbate-analyte interactions. We also find that alloying cPs and cMOFs enables
facile thin film co-processing and device integration, potentially unlocking
the use of these hybrid conductors in diverse electronic applications.
