Bi-component MOF-derived high-sensitive triethylamine gas sensors based on MoO₃/ZnMoO₄/CoMoO₄ hierarchical structures effectuated by tunable surface/interface transfer behavior

One-dimensional MoO₃/ZnMoO₄/CoMoO₄ hierarchical structures with sequential layered and granulated constitutional units on surfaces have been successfully designed and fabricated, mainly derived through the introducing of bi-component MOF and the effective element migration mechanism. Based on the different adding ratios of Co and Zn sources, the obtained hierarchical structure can be composed of the central MoO₃ nanobelts, the outer uniform ZnMoO₄ shell, and the outermost tunable CoMoO₄ nanoparticles. The well-organized ZnMoO₄ shell and CoMoO₄ nanoparticles grown on MoO₃ surface provide favorable opportunities for improving the surface absorption and chemical reaction, electron transport paths, and electron transfer efficiency. Compared with MoO₃ nanobelts and MoO₃/ZnMoO₄ composites, the optimal MoO₃/ZnMoO₄/CoMoO₄ sensors exhibit superior gas-sensing response value of 505.67 for 10 ppm triethylamine (TEA) at 270 °C as well as excellent gas selectivity and long-term stability. The superior gas-sensing performance is mainly attributed to the combination of the designed multi-level effective heterojunctions, large specific surface area, the enhanced surface adsorption/reaction, and the particular surface/interface electron transport process. More importantly, the current work presents a new insight of original gas-sensing MoO₃/ZnMoO₄/CoMoO₄ hierarchical structures for detecting the variation of freshness in shrimp storage, indicating the practical applications in chemical detector and biosensor fields.