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A novel three‐phase composite of Co/CoO/Co3O4 is synthesized through straightforward calcination treatment towards cobalt‐based metal‐organic gel (Co MOG) precursor, which is constructed with the metal source of cobalt chloride and organic ligand of 4, 4', 4"‐((1, 3, 5‐triazine‐2, 4, 6‐triyl) tris (azanediyl)) tribenzoic acid at room temperature. The morphology, structure and composition of the derived Co/CoO/Co3O4 is confirmed through scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X‐ray diffraction (XRD) and X‐ray photoelectron spectrums (XPS). Furthermore, the composite of Co/CoO/Co3O4 is employed as electrode modified material with the excellent electrochemical performances of accelerating the electron transfer and boosting the electrode interface reaction. As a proof of concept, the electrochemical redox behaviors of diethylstilbestrol (DES) have been systemically investigated at the modified electrode interface and the established analytical approach for DES with the broad linear range and satisfied recovery. This work not only provided a facile approach to obtain electrode material with excellent electrochemical performance but also enriched the application of MOG materials in the electrochemical field. [ABSTRACT FROM AUTHOR]

Detecting hydrogen sulfide (H 2 S) odor gas in the environment at parts-per-billion-level concentrations is crucial. However, a significant challenge is the rapid deactivation caused by SO 4 2- deposition. To address this issue, we developed a sensing material comprising Fe 2 O 3 -decorated WO 3 nanowires (FWO) with strong interfacial interaction. During the H 2 S sensing process, important oxygen vacancies (OVs) are generated in situ and are recyclable on the surface of the Fe 2 O 3 cluster. This sensor achieves a response of 140 (Ra/Rg) toward 50 ppm of H 2 S at 250 °C, with an experimentally measured detection limit of 1 ppb. It also exhibits remarkable stability, with no significant change observed over a long period of 150 days. Based on a combination of in situ DRIFT and DFT calculations, we have identified that the overactivation of O 2 is the key step in the formation of SO 4 2- . This overactivation can be partially modulated by the synergistic effect of Fe 2 O 3 decoration and the in situ generated OVs, regulating the oxidation product to SO 2 rather than the toxic SO 4 2- . Furthermore, the continuous generation of OVs compensates for the loss of active sites pertaining to SO 4 2- deposition, thereby contributing to the excellent stability of the sensor. This study underscores the beneficial impact of in situ OV generation in FWO for H 2 S sensing, offering a dynamic strategy to enhance sensor performance, particularly in terms of stability.