The precise design of material electronic structure and surface characteristics, achieved through a unique multi-level synergy of oxygen vacancies, heterojunctions, and facet-selective catalysis, is vital to enhancing the sensitivity and selectivity of electrochemical sensors for reliable trace detection in complex environments. Herein, we developed a novel electrochemical sensor based on Au/Co 3 O 4 -C/Fe-MOF for ultrasensitive and selective determination of chlorpyrifos (CPF). Specifically, the oxygen vacancy defects in Co 3 O 4 -C/Fe-MOF effectively enhance CPF adsorption, and the formation of p-n heterojunctions optimizes interfacial charge transfer kinetics, thereby improving the detection sensitivity for trace CPF. Meanwhile, Au nanoparticles not only function as efficient co-catalysts to further enhance sensitivity, but also impart excellent selectivity to the sensor through their specific facet effects. Theoretical calculations demonstrate that the most abundantly exposed Au (111) crystal plane possess the strongest selective adsorption capability for CPF. This unique multi-level synergy collectively ensuring superior sensor performance. The constructed electrochemical sensor exhibited a broad linear detection range of 1 pM to 50 μM with an ultralow detection limit of 0.8 pM (S/N = 3), while exhibiting excellent stability, sensitivity, and reproducibility for reliable real sample detection. This multi-level synergistic strategy integrating defect engineering, interface modulation, and surface functionalization not only provides novel insights for design of functional sensing materials, but also opens new avenues for developing high-performance pesticide detection platforms. • Au/Co 3 O 4 -C/Fe-MOF was in situ fixed on nickel foam through self-assembly strategy. • Synergistic effect of oxygen vacancies and p-n heterojunction enhances sensor sensitivity. • Au nanoparticles as co-catalysts enhance sensitivity and selectivity via specific face effects. • Au (111) crystal plane exhibits the highest selective adsorption capability for chlorpyrifos. • A high-performance electrochemical sensor was established for trace chlorpyrifos assay.
Zhang et al. (Sun,) studied this question.