Pérez-Álvarez Jorge, Tojo Concha, Buceta David, López-Quintela M Arturo
Physical Chemistry Department, University of Vigo E-36310 Vigo Spain
Laboratorio de Magnetismo y Nanotecnología, University of Santiago de Compostela E-15782 Santiago de Compostela Spain
RSC Adv. 2020 Nov 19;10(69):42277-42286. doi: 10.1039/d0ra08227a. eCollection 2020 Nov 17.
Au/Pt nanoparticles show an optimized catalytic activity when compared with Pt nanoparticles because Pt activity is improved by the presence of Au on the surface. It was checked whether a controllable surface composition can be achieved by the simple strategy of varying the Au : Pt ratio. We present an in-depth kinetic simulation study on the influence of Au : Pt ratio on the formation of Au/Pt nanoparticles synthesized in microemulsions. This study is able to explain the resulting nanoarrangement as a function of kinetic parameters such as Au : Pt ratio and intermicellar exchange rate. The role of the micelles as a dosing pump of the Au precursor explains that a higher Au amount results in a Au reduction which takes place over a longer period of time. It implies that Au is deposited until longer stages of the synthesis, so Au is present at the nanoparticle surface. Micelles as reaction media produce a minor impact on Pt due to its slower reduction. These different kinetic behaviours of Au and Pt give rise to a surface composition which can be tailored by tuning the Au : Pt ratio. Numerical results on surface composition successfully reproduce experimental data and further support the outcomes of the degree of atomic mixing under different Au : Pt ratios.
与铂纳米颗粒相比，金/铂纳米颗粒表现出优化的催化活性，因为金在表面的存在提高了铂的活性。研究了通过改变金：铂比例的简单策略是否可以实现可控的表面组成。我们对金：铂比例对微乳液中合成的金/铂纳米颗粒形成的影响进行了深入的动力学模拟研究。该研究能够解释所得纳米排列与诸如金：铂比例和胶束间交换速率等动力学参数的函数关系。胶束作为金前驱体的计量泵的作用解释了较高的金含量导致金的还原在更长的时间内发生。这意味着金在合成的更长阶段沉积，因此金存在于纳米颗粒表面。由于铂的还原较慢，胶束作为反应介质对铂产生的影响较小。金和铂的这些不同动力学行为导致了一种可以通过调节金：铂比例来定制的表面组成。表面组成的数值结果成功地再现了实验数据，并进一步支持了不同金：铂比例下原子混合程度的结果。
