Mihai Marius Alexandru, Spataru Tanta, Somacescu Simona, Moga Olivia Georgeta, Preda Loredana, Florea Mihaela, Kuncser Andrei, Spataru Nicolae
Institute of Physical Chemistry "Ilie Murgulescu", 202 Spl. Independenţei, 060021, Bucharest, Romania.
National Institute of Materials Physics, 405A Atomistilor Street, 077125 Magurele, Romania.
Analyst. 2023 Nov 20;148(23):6028-6035. doi: 10.1039/d3an01249b.
Hydrothermally formed mesoporous SnO was used as a support for nickel chemical deposition and, after subsequent thermal treatment, a high specific surface area (36 m g) Ni/SnO material was obtained. XPS analysis has shown that in the Sn 3d region the spectrum is similar to that of pristine SnO, whereas Ni species are present on the surface as NiO, NiO and Ni(OH). Mixing Ni/SnO with a small amount of Black Pearls (BP) leads to a significant enhancement of the resulting Ni/SnO-BP composite activity for nitrite anodic oxidation, presumably due to the higher surface area (115 m g), to better electrical conductivity and to a certain contribution of the BP to an increase in surface density of the active sites. Ni/SnO-BP also outperforms pristine BP (in terms of Tafel slopes and electron-transfer rates), most likely due to the fact that the Ni(II)/Ni(III) couple can act as an electrocatalyst for nitrite oxidation. A voltammetric method is proposed for the determination of nitrite, over a concentration range of three orders of magnitude (0.05 to 20 mM), with good reproducibility, high stability and excellent sensitivity. The high upper limit of the dynamic range of the analytically useful response might provide a basis for the reliable quantification of nitrite in wastewater.
水热法制备的介孔SnO用作镍化学沉积的载体，经过后续热处理后，得到了高比表面积（36 m²/g）的Ni/SnO材料。XPS分析表明，在Sn 3d区域，光谱与原始SnO的光谱相似，而镍物种以NiO、Ni₂O₃和Ni(OH)的形式存在于表面。将Ni/SnO与少量黑珍珠（BP）混合，可显著提高所得Ni/SnO-BP复合材料对亚硝酸盐阳极氧化的活性，这可能是由于其较高的比表面积（115 m²/g）、更好的导电性以及BP对活性位点表面密度增加的一定贡献。Ni/SnO-BP在塔菲尔斜率和电子转移速率方面也优于原始BP，这很可能是因为Ni(II)/Ni(III)电对可作为亚硝酸盐氧化的电催化剂。提出了一种伏安法测定亚硝酸盐，其浓度范围为三个数量级（0.05至20 mM），具有良好的重现性、高稳定性和出色的灵敏度。分析有用响应的动态范围的高上限可能为可靠定量废水中的亚硝酸盐提供依据。
