Petriev Iliya, Pushankina Polina, Lutsenko Ivan, Shostak Nikita, Baryshev Mikhail
Department of Physics, Kuban State University, 350040 Krasnodar, Russia.
Laboratory of Problems of Stable Isotope Spreading in Living Systems, Southern Scientific Centre of the RAS, 344000 Rostov-on-Don, Russia.
Nanomaterials (Basel). 2020 Oct 21;10(10):2081. doi: 10.3390/nano10102081.
The method of synthesis of bimetallic Pd-Ag pentagonally structured catalyst "nanostar" on the surface of Pd-23%Ag alloy films has been developed. The resulting catalyst was studied as a highly active functional layer for methanol oxidation reaction (MOR) in alkaline media and the intensification of hydrogen transport through the Pd-23%Ag membrane in the processes of hydrogen diffusion purification. A modifying layer with a controlled size, composition and excellent electrocatalytic activity was synthesized by electrochemical deposition at a reduced current density compared to classical methods. The low deposition rate affects the formation of pentagonally structured nanocrystallites, allowing Pd and Ag particles to form well-defined structures due to the properties of the surfactant used. Electrochemical studies have demonstrated that the catalyst synthesized by the "nanostar" method shows better electrocatalytic activity in relation to MOR and demonstrates a higher peak current (up to 17.82 µA cm) in comparison with one for the catalyst synthesized by the "nanoparticle" method (up to 10.66 µA cm) in a cyclic voltammetric study. The nanostar catalyst electrode releases the highest current density (0.25 µA cm) for MOR and demonstrates higher catalytic activity for the oxidation of possible intermediates such as sodium formate in MOR. In the processes of diffusion membrane purification of hydrogen, a multiple increase in the density of the penetrating flux of hydrogen through the membranes modified by the "nanostar" catalyst (up to 10.6 mmol s m) was demonstrated in comparison with the membranes modified by the "nanoparticles" method (up to 4.49 mmol s m). Research data may indicate that the properties of the developed pentagonally structured catalyst "nanostar" and its enhanced activity with respect to reactions involving hydrogen increase the desorption activity of the membrane, which ultimately accelerates the overall stepwise transfer of hydrogen across the membrane.
已开发出在 Pd-23%Ag 合金膜表面合成双金属 Pd-Ag 五角结构催化剂“纳米星”的方法。所得催化剂被研究用作碱性介质中甲醇氧化反应（MOR）的高活性功能层，以及在氢扩散净化过程中强化氢通过 Pd-23%Ag 膜的传输。与传统方法相比，通过在降低的电流密度下进行电化学沉积，合成了具有可控尺寸、组成和优异电催化活性的改性层。低沉积速率影响五角结构纳米微晶的形成，由于所用表面活性剂的性质，使得 Pd 和 Ag 颗粒形成明确的结构。电化学研究表明，通过“纳米星”方法合成的催化剂对 MOR 表现出更好的电催化活性，并且在循环伏安研究中，与通过“纳米颗粒”方法合成的催化剂相比，显示出更高的峰值电流（高达 17.82 μA/cm²）（高达 10.66 μA/cm²）。纳米星催化剂电极对 MOR 释放出最高电流密度（0.25 μA/cm²），并对 MOR 中可能的中间体如甲酸钠的氧化表现出更高的催化活性。在氢的扩散膜净化过程中，与用“纳米颗粒”方法改性的膜（高达 4.49 mmol·s⁻¹·m⁻²）相比，用“纳米星”催化剂改性的膜的氢渗透通量密度有了成倍增加（高达 10.6 mmol·s⁻¹·m⁻²）。研究数据可能表明，所开发的五角结构催化剂“纳米星”的性质及其对涉及氢的反应的增强活性提高了膜的解吸活性，最终加速了氢在膜上的整体逐步传输。
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