CoO dodecahedeons with abundant trivalent cobalt cation (Co) and surface absorbed oxygen species were prepared via regulating calcination temperature and heating rate of Co-based metal-organic framework (ZIF-67) templates. The influence of the calcination temperature and heating rate on the relative content of trivalent cobalt cation has been discussed in detail. The gas-sensing experiment demonstrates that the CoO dodecahedeons with abundant active Co exhibit significantly enhanced response to CO and a low detection limit (≤500 ppb). The response value is 20 times higher than that of CoO nanoparticles to CO at the relatively low temperature of 150 °C and exhibits rapid response-recovery, good stability, reproducibility and selectivity. Such superior sensing performance to CO is mainly due to the accessible octahedral trivalent cobalt cation active sites and abundant absorbed-oxygen species as well as the large specific surface area which is beneficial to CO absorption, diffusion and the surface redox reaction. This facile method sheds light on the reasonable design of CoO with different relative content of trivalent cobalt ion. The results afford decisive insights to realize the influence of Co on the gas-sensing performance to CO, which allows new choices to design highly sensitive gas sensors.

中文翻译：

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金属有机框架衍生的多孔 Co3O4 十二面体，具有丰富的活性 Co3+，用于 ppb 级 CO 气体传感


通过调节钴基金属有机骨架（ZIF-67）模板的煅烧温度和加热速率，制备了富含三价钴阳离子（Co）和表面吸收氧的CoO十二面体。详细讨论了焙烧温度和升温速率对三价钴阳离子相对含量的影响。气敏实验表明，含有丰富活性Co的CoO十二面体对CO的响应显着增强，且检测限较低（≤500ppb）。在150℃的较低温度下，其响应值比CoO纳米颗粒对CO的响应值高20倍，并且表现出快速的响应恢复、良好的稳定性、重现性和选择性。这种优异的CO传感性能主要归因于易接近的八面体三价钴阳离子活性位点和丰富的吸附氧物种以及有利于CO吸收、扩散和表面氧化还原反应的大比表面积。这种简便的方法为不同三价钴离子相对含量的CoO的合理设计提供了思路。这些结果为认识 Co 对 CO 气体传感性能的影响提供了决定性的见解，从而为设计高灵敏度气体传感器提供了新的选择。