Bimetallic alloys of Pt and Rh or Ir were prepared with pulsed laser deposition (PLD) on a well-ordered MgO(100) substrate, leading to epitaxial growth along the [001] plane, as confirmed by surface analysis techniques. The out-of-equilibrium conditions of PLD allowed the exploration of a range of compositions for which phase separation would instead be expected. The electrochemistry of a series of PtRh and PtIr (100) alloys was investigated in 0.5 M H₂SO₄, showing a surprisingly intense electrocatalytic activity towards the reduction of nitrate for a Pt content of 21–42%. These alloys feature a lower reaction overpotential with respect to Rh and Ir while outperforming the pure metals in terms of reduction current. A detailed analysis of the voltammetric features with respect to alloy composition highlighted a correlation between hydrogen desorption and nitrate reduction activity. In addition, an optimal potential range for nitrate reduction, common to PtRh and PtIr alloys, was observed, corresponding to the potential window in which nitrate adsorption coincides with of fast reduction of the key reaction intermediate NO_ads.

中文翻译：

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通过优先取向的（100）PtRh和PtIr合金增强电催化硝酸盐的还原：“混溶间隙”的隐藏宝藏

Pt和Rh或Ir的双金属合金是通过在有序MgO（100）衬底上进行脉冲激光沉积（PLD）制备的，这导致了沿[001]平面的外延生长，这已通过表面分析技术得到证实。PLD的不平衡条件允许探索一系列可能期望发生相分离的成分。在0.5 MH ₂ SO _4中研究了一系列PtRh和PtIr（100）合金的电化学在Pt含量为21-42％时，对硝酸盐的还原显示出惊人的强烈电催化活性。这些合金相对于Rh和Ir具有较低的反应过电势，同时在还原电流方面优于纯金属。关于合金成分的伏安特性的详细分析突出了氢解吸和硝酸盐还原活性之间的相关性。此外，最佳的电位范围为硝酸盐还原，通用于PtRh和PTIR合金，观察到，对应于该电位窗口，其中吸附硝酸重合快速还原的关键反应中间体NO的_广告。