The bulk properties and chemical reactivity of disordered Pt-Ni alloys in the A1 (fcc) structure are investigated using different methods: Virtual Crystal Approximation (VCA), Korringa–Kohn–Rostoker Coherent Potential Approximation (KKR-CPA), and large explicit supercells generated using Super-Cell Random Approximates (SCRAPs). While VCA predicts lattice constants that closely follow Vegard’s law, the large supercells and KKR-CPA predict lattice constants that are consistently larger than Vegard’s law. KKR-CPA results closely agree with those from the large supercells for the disordered alloys, producing similar projected density of states and magnetic moment across the composition range. For instance, while VCA predicts the disordered alloys to be non-magnetic at a Pt concentration (x_Pt) ≥ 0.5, KKR-CPA and SCRAPs predict the disordered alloys to remain ferromagnetic to higher Pt concentrations. As x_Pt decreases, the adsorption of H becomes more exothermic on bulk-terminated (111) surfaces but less exothermic on Pt monolayer-terminated (111) surfaces due largely to strain effects. (111) surfaces cut from the large supercells predict average H adsorption energies on the disordered alloys similar to those on the ordered phases of the same compositions, while VCA predicts H adsorption to be more exothermic.

使用不同的方法研究了A1（fcc）结构中无序Pt-Ni合金的整体性质和化学反应性：虚拟晶体近似（VCA），Korringa-Kohn-Rostoker相干势近似（KKR-CPA）和大型显式超晶胞使用超级单元随机逼近（SCRAP）生成。VCA预测晶格常数严格遵循Vegard律，而大型超级电池和KKR-CPA预测晶格常数始终大于Vegard律。KKR-CPA结果与无序合金大型超级电池的结果非常吻合，在整个成分范围内产生相似的预计态密度和磁矩。例如，VCA预测无序合金在Pt浓度下为非磁性（x_Pt）≥0.5，KKR-CPA和SCRAPs预测无序合金在较高的Pt浓度下仍保持铁磁性。随着x _Pt的减少，H的吸附在本体末端（111）的表面上放热更多，而在Pt单层末端（111）的表面上放热更少，这主要是由于应变效应。（111）从大型超级电池上切下的表面预测无序合金上的平均H吸附能类似于相同组成的有序相上的平均H吸附能，而VCA预测H吸附会放热更多。