Feng Zhenyu, Gao Cuiling, Ma Xicheng, Zhan Jinhua
Key Laboratory for Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University Jinan Shandong 250100 P. R. China
Shandong Institute for Product Quality Inspection Jinan Shandong 250102 P. R. China.
RSC Adv. 2019 Dec 20;9(72):42351-42359. doi: 10.1039/c9ra09705h. eCollection 2019 Dec 18.
The extensive use of chlorobenzene in chemical, pharmaceutical, and agrochemical industries poses a severe health hazard to human beings, because it is highly toxic. The detection of chlorobenzene by metal oxide gas sensors is difficult, owing to its chemically inert molecular structure. In this study, well-dispersed Pd nanoparticles were deposited on porous ZnO nanoplates surface ion exchange, followed by H reduction. The preparation process effectively prevented the aggregation and uncontrollable growth of Pd particles. A gas-sensing test was conducted, and the modification of size-controlled Pd nanoparticles was found to effectively enhance the sensing properties of porous ZnO nanoplates to chlorobenzene over 300 °C (higher sensitivity at a low operating temperature). At 440 °C, 5% Pd@ZnO sensor showed a drastic increase in response by nearly 4.5-fold, as well as excellent sensing selectivity to chlorobenzene. Its repeatability and stability were acceptable. As known, Pd nanocatalysts contribute to the oxidation of chlorinated aromatic compounds. Pd@ZnO sensors generated more catalytic sites and oxygen species (confirmed by XPS), thus enhancing chlorobenzene oxidation and improving the sensitivity of ZnO-based gas sensors.
氯苯在化学、制药和农用化学品工业中的广泛使用对人类健康构成了严重危害，因为它具有高毒性。由于氯苯化学惰性的分子结构，利用金属氧化物气体传感器检测氯苯很困难。在本研究中，通过表面离子交换将分散良好的钯纳米颗粒沉积在多孔氧化锌纳米片上，随后进行氢气还原。该制备过程有效地防止了钯颗粒的聚集和不可控生长。进行了气敏测试，结果发现尺寸可控的钯纳米颗粒的改性有效地提高了多孔氧化锌纳米片在300℃以上对氯苯的传感性能（在低工作温度下具有更高的灵敏度）。在440℃时，5% Pd@ZnO传感器的响应急剧增加近4.5倍，并且对氯苯具有优异的传感选择性。其重复性和稳定性是可接受的。众所周知，钯纳米催化剂有助于氯化芳香化合物的氧化。Pd@ZnO传感器产生了更多的催化位点和氧物种（通过XPS证实），从而增强了氯苯氧化并提高了氧化锌基气体传感器的灵敏度。
