Layered double hydroxides (LDH) have attracted much attention in the gas sensing field due to their unique laminate structure and flexible chemical composition. In this work, the single crystalline nanosheet-assembled ZnCo-LDHs are synthesized by a facile one-pot hydrothermal route. We find that the Zn addition amount plays a vital role in tuning the Co²⁺/Co³⁺ ratio distributed in the laminate structure of LDH, further modulating the amount of oxygen defects. When the Zn/Co addition ratio is 1.8 in the synthetic system, the obtained ZnCo-LDH exhibits abundant exposed active sites due to its orderly arranged nanosheet structure. It also shows a favorable oxygen adsorption capability resulting from more oxygen defects in the laminate structure. The hierarchical structure facilitates gas diffusion and catalysis in sensing the redox process by cooperation of Zn²⁺ and Co³⁺. The obtained flower like ZnCo-LDH exhibits a high response of 19.19 to 200 ppm ethanol at working temperature as low as 80 °C. It also shows good selectivity and stability. The hierarchical ZnCo-LDHs provide a new chemiresistive sensing material with low energy consumption and high sensitivity.

中文翻译：

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层状结构对多级锌钴层状双氢氧化物形貌和乙醇传感性能的影响

层状双氢氧化物（LDH）因其独特的层状结构和灵活的化学成分而在气敏领域备受关注。在这项工作中，单晶纳米片组装的 ZnCo-LDHs 通过简单的一锅水热路线合成。我们发现Zn的添加量对于调节LDH层状结构中分布的Co ²⁺ /Co ³⁺比例起着至关重要的作用，从而进一步调节氧缺陷的数量。当合成体系中Zn/Co添加比例为1.8时，所得ZnCo-LDH由于其有序排列的纳米片结构而表现出丰富的暴露活性位点。由于层压结构中存在更多的氧缺陷，它还显示出良好的氧吸附能力。通过Zn ²⁺和Co ³⁺的配合，分层结构有利于气体扩散和催化氧化还原过程的传感。获得的花状ZnCo-LDH在低至80℃的工作温度下表现出19.19至200ppm乙醇的高响应。它还表现出良好的选择性和稳定性。分层ZnCo-LDHs提供了一种低能耗、高灵敏度的新型化学电阻传感材料。