Bampos Georgios, Bebelis Symeon
Department of Chemical Engineering, University of Patras, GR-26504 Patras, Greece.
Nanomaterials (Basel). 2024 Mar 11;14(6):500. doi: 10.3390/nano14060500.
A series of carbon black-supported 7.5 wt.% Pd-2.5 wt.% M/C (M: Ag, Ca, Co, Cu, Fe, Ni, Ru, Sn, Zn) electrocatalysts, synthesized via the wet impregnation method, and reduced at 300 °C, were compared in terms of their hydrogen oxidation reaction (HOR) activity in a 0.1 M KOH solution using the thin-film rotating-disk electrode technique. Moreover, 10 wt.% Pd/C and 10 wt.% Pt/C electrocatalysts were prepared in the same manner and used as references. The 7.5 wt.% Pd-2.5 wt.% Ni/C electrocatalyst exhibited the highest HOR activity among the Pd-based electrocatalysts, although it was lower than that of the 10 wt.% Pt/C. Its activity was also found to be higher than that of Pd-Ni electrocatalysts of the same total metal loading (10 wt.%) and reduction temperature (300 °C) but of different Pd to Ni atomic ratio. It was also higher than that of 7.5 wt.% Pd-2.5 wt.% Ni/C electrocatalysts that were reduced at temperatures other than 300 °C. The superior activity of this electrocatalyst was attributed to an optimum value of the hydrogen binding energy of Pd, which was induced by the presence of Ni (electronic effect), as well as to the oxophilic character of Ni, which favors adsorption on the Ni surface of hydroxyl species that readily react with adsorbed hydrogen atoms on neighboring Pd sites in the rate-determining step.
通过湿浸渍法合成并在300℃下还原的一系列炭黑负载的7.5 wt.% Pd-2.5 wt.% M/C（M：Ag、Ca、Co、Cu、Fe、Ni、Ru、Sn、Zn）电催化剂，采用薄膜旋转圆盘电极技术在0.1 M KOH溶液中对其氢氧化反应（HOR）活性进行了比较。此外，以相同方式制备了10 wt.% Pd/C和10 wt.% Pt/C电催化剂并用作参考。7.5 wt.% Pd-2.5 wt.% Ni/C电催化剂在基于钯的电催化剂中表现出最高的HOR活性，尽管它低于10 wt.% Pt/C的活性。还发现其活性高于相同总金属负载量（10 wt.%）和还原温度（300℃）但钯与镍原子比不同的Pd-Ni电催化剂。它也高于在300℃以外的温度下还原的7.5 wt.% Pd-2.5 wt.% Ni/C电催化剂。这种电催化剂的优异活性归因于镍的存在（电子效应）诱导的钯的氢结合能的最佳值，以及镍的亲氧特性，这有利于在速率决定步骤中与相邻钯位点上吸附的氢原子容易反应的羟基物种在镍表面的吸附。
