Alam Md Mahbubul, Rashed Md A, Rahman Md Musfiqur, Rahman Mohammed M, Nagao Yuki, Hasnat Mohammad A
Department of Chemistry, Shahjalal University of Science and Technology Sylhet-3114 Bangladesh
Department of Chemistry, Mawlana Bhashani Science and Technology University Santosh, Tangail-1902 Bangladesh.
RSC Adv. 2018 Feb 20;8(15):8071-8079. doi: 10.1039/c7ra12576c. eCollection 2018 Feb 19.
Pd nanoparticles were electrochemically immobilized on a Pt surface in the presence of sodium dodecyl sulfate (SDS) molecules to study the electrokinetics of arsenite oxidation reactions and the corresponding sensing activities. The X-ray photoelectron spectroscopy (XPS) analysis showed that on the Pt surface, Pd atoms exist as adatoms and the contents of Pd(0) and Pd(ii) were 75.72 and 24.28 at%, respectively, and the particle sizes were in the range of 61-145 nm. The experimental results revealed that the catalytic efficiency as well as the charge transfer resistance (at the redox potential of the Fe(ii)/Fe(iii) couple) increased in the order of Pt < Pt-Pd < Pt-Pd. A Pt-Pd electrode exhibited an open circuit potential (OCP) of 0.65 V in acidic conditions; however, when 50.0 mM NaAsO was present, the OCP value shifted to 0.42 V. It has been projected that the As(iii) oxidation proceeds using a sequential pathway: As(iii) → As(iv) → As(v). After optimization of the square wave voltammetric data, the limits of detection of As(iii) were obtained as 1.3 μg L and 0.2 μg L when the surface modification of the Pt surface was executed with Pd particles in the absence and presence of the SDS surfactant, respectively. Finally, real samples were analyzed with excellent recovery performance.
在十二烷基硫酸钠（SDS）分子存在的情况下，将钯纳米颗粒电化学固定在铂表面，以研究亚砷酸盐氧化反应的动电现象及相应的传感活性。X射线光电子能谱（XPS）分析表明，在铂表面，钯原子以吸附原子形式存在，Pd(0)和Pd(ii)的含量分别为75.72at%和24.28at%，粒径范围为61-145nm。实验结果表明，催化效率以及电荷转移电阻（在Fe(ii)/Fe(iii)电对的氧化还原电位下）按Pt < Pt-Pd < Pt-Pd的顺序增加。在酸性条件下，Pt-Pd电极的开路电位（OCP）为0.65V；然而当存在50.0mM NaAsO时，OCP值移至0.42V。据推测，As(iii)的氧化通过连续途径进行：As(iii)→As(iv)→As(v)。在对方波伏安数据进行优化后，当在不存在和存在SDS表面活性剂的情况下用钯颗粒对铂表面进行表面修饰时，As(iii)的检测限分别为1.3μg L和0.2μg L。最后，对实际样品进行了分析，回收率极佳。
