A Dual Sensing Platform for Human Exhaled Breath Enabled by Fe‐MIL‐101‐NH₂ Metal–Organic Frameworks and its Derived Co/Ni/Fe Trimetallic Oxides

Abstract Limited by the insufficient active sites and the interference from breath humidity, designing reliable gas sensing materials with high activity and moisture resistance remains a challenge to analyze human exhaled breath for the translational application of medical diagnostics. Herein, the dual sensing and cooperative diagnosis is achieved by utilizing metal‐organic frameworks (MOFs) and its derivative. The Fe‐MIL‐101‐NH₂ serves as the quartz crystal microbalance humidity sensing layer, which exhibits high selectivity and rapid response time (16 s/15 s) to water vapor. Then, the Co²⁺ and Ni²⁺ cations are further co‐doped into Fe‐MIL‐101‐NH₂ host to obtain the derived Co/Ni/Fe trimetallic oxides (CoNiFe‐MOS‐n). The chemiresistive CoNiFe‐MOS‐n sensor displays the high sensitivity (560) and good selectivity to acetone, together with a lower original resistance compared with Fe₂O₃ and NiFe₂O₄. Moreover, as a proof‐of‐concept application, synergistic integration of Fe‐MIL‐101‐NH₂ and derived CoNiFe‐MOS‐n is carried out. The Fe‐MIL‐101‐NH₂ is applied as moisture sorbent materials, which realize a sensitivity compensation of CoNiFe‐MOS‐n sensors for the detection of acetone (biomarker gas of diabetes). The findings provide an insight for effective utilization of MOFs and the derived materials to achieve a trace gas detection in exhaled breath analysis.