School of Environmental Science, Nanjing Xiaozhuang University, Nanjing 211171, China.
Molecules. 2022 Dec 23;28(1):99. doi: 10.3390/molecules28010099.
The electrocatalytic characteristics of nanostructures are significantly affected by surface structure. The strict regulation of structural characteristics is highly beneficial for the creation of novel nanocatalysts with enhanced electrocatalytic performance. This work reports a nitrite electrochemical sensor based on novel flower-like Pd-ZnO nanostructures. The Pd-ZnO nanocatalysts were synthesized through a simple hydrothermal method, and their morphology and structure were characterized via field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Their electrocatalytical performance in the nitrite oxidation reaction was studied via cyclic voltammetry (CV) and the amperometric technique. Compared to pure ZnO and Pd nanoparticles, the Pd-ZnO nanostructures exhibited enhanced electrochemical performance in the nitrite oxidation reaction. In order to investigate the relationships between the structures of Pd-ZnO nanocatalysts and the corresponding electrocatalytic performances, different surface morphologies of Pd-ZnO nanocatalysts were fabricated by altering the solution pH. It was found that the flower-like Pd-ZnO nanostructures possessed larger effective surface areas and faster electron transfer rates, resulting in the highest electrocatalytic performance in the nitrite oxidation reaction. The designed nitrite sensor based on flower-like Pd-ZnO displayed a wide concentration linear range of 1 μM-2350 μM, a low detection limit of 0.2 μM (S/N of 3), and high sensitivity of 151.9 μA mM cm. Furthermore, the proposed sensor exhibited perfect selectivity, excellent reproducibility, and long-time stability, as well as good performance in real sample detection.
纳米结构的电催化特性受表面结构的影响显著。对结构特征的严格调控非常有利于创造具有增强电催化性能的新型纳米催化剂。本工作报道了一种基于新型花状 Pd-ZnO 纳米结构的亚硝酸盐电化学传感器。Pd-ZnO 纳米催化剂通过简单的水热法合成，并通过场发射扫描电子显微镜 (FE-SEM)、X 射线光电子能谱 (XPS) 和 X 射线衍射 (XRD) 对其形貌和结构进行了表征。通过循环伏安法 (CV) 和安培技术研究了它们在亚硝酸盐氧化反应中的电催化性能。与纯 ZnO 和 Pd 纳米粒子相比，Pd-ZnO 纳米结构在亚硝酸盐氧化反应中表现出增强的电化学性能。为了研究 Pd-ZnO 纳米催化剂的结构与相应电催化性能之间的关系，通过改变溶液 pH 值来制备不同表面形态的 Pd-ZnO 纳米催化剂。研究发现，花状 Pd-ZnO 纳米结构具有更大的有效表面积和更快的电子转移速率，从而在亚硝酸盐氧化反应中表现出最高的电催化性能。基于花状 Pd-ZnO 的设计亚硝酸盐传感器具有 1 μM-2350 μM 的宽浓度线性范围、0.2 μM（S/N 为 3）的低检测限和 151.9 μA mM cm 的高灵敏度。此外，该传感器表现出完美的选择性、优异的重现性和长期稳定性，以及在实际样品检测中的良好性能。
