Bimetallic nanocrystals (NCs) have obtained significant attention due to their unique advantages of the intrinsic properties of individual metals and synergistic enhancements resulting from the electronic coupling between two constituent metals. In this work, Pd@Pt core–shell NCs were prepared through a facile one-pot solution-phase method, which had excellent dispersion and uniform size. Concurrently, ZnO nanosheets were prepared via a hydrothermal method. To explore their potential in nitrogen dioxide (NO₂) gas sensing applications, sensitive materials based on ZnO nanosheets with varying mass percentages of Pd@Pt NCs were generated through an impregnation process. The sensor based on 0.3 wt % Pd@Pt-ZnO exhibited remarkable performance, demonstrating a substantial response (R_g/R_a = 60.3) to 50 ppb of NO₂ at a low operating temperature of 80 °C. Notably, this sensor reached an outstanding low detection limit of 300 ppt. The enhancement in gas sensing capabilities can be attributed to the sensitization and synergistic effects imparted by the exceptional catalytic activity of Pd@Pt NCs, which significantly promoted the reaction. This research introduces a novel approach for the utilization of core–shell structured bimetallic nanocrystals as modifiers in metal-oxide-semiconductor (MOS) materials for NO₂ detection.

中文翻译：

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用于 ppt 级 NO2 检测的 Pd@Pt 核壳纳米晶体装饰的 ZnO 纳米片

双金属纳米晶体（NC）由于其单一金属的固有特性的独特优势以及两种金属之间的电子耦合产生的协同增强而受到了极大的关注。在这项工作中，通过简便的一锅溶液相法制备了Pd@Pt核壳NCs，其具有优异的分散性和均匀的尺寸。同时，通过水热法制备了ZnO纳米片。为了探索其在二氧化氮 (NO ₂ ) 气体传感应用中的潜力，通过浸渍过程生成了基于 ZnO 纳米片且具有不同质量百分比的 Pd@Pt NC 的敏感材料。基于0.3 wt% Pd@Pt-ZnO 的传感器表现出卓越的性能，在80 °C 的低工作温度下对50 ppb NO 2 具有显着的响应（_R g / _Ra = _60.3）。值得注意的是，该传感器达到了 300 ppt 的出色检测下限。气体传感能力的增强可归因于Pd@Pt NCs优异的催化活性所带来的敏化和协同效应，显着促进了反应。这项研究介绍了一种利用核壳结构双金属纳米晶体作为金属氧化物半导体（MOS）材料中的改性剂进行 NO ₂检测的新方法。