Single-atom catalysts (SACs), including metal-metal-bonded bimetallic ones named single-atom alloys (SAAs), have aroused significant interest in catalysis. In this article, the catalytic mechanism and bonding analysis of CO oxidation reaction on bimetallic gold-palladium (Au-Pd) model of single atom alloy Au₃₇Pd₁ are investigated by using quantum chemical calculations. The molecular geometries and adsorbate/substrate binding energies of CO@Au-Pd, O₂@Au-Pd and CO/O₂@Au-Pd configurations are identified. The core-shell structure is confirmed to be the most stable structure for Au-Pd SAA, where the Pd atom prefers to situate at the core site. Charge transfer from the Pd atom to the Au atoms has been confirmed to stabilize the structure. According to the binding energy and chemical bonding analysis, both CO and O₂ prefer to bind to the Pd atom at the hex site with low coordination number. The formation of new co-adsorption species is identified, in which vertical and parallel bridging adsorptions of CO and O₂ on the Au-Pd bonds are observed. CO oxidation on Au-Pd SAA is found to be feasible with low energy barriers and follows the Langmuir-Hinshewood (L-H) mechanism. Our work offers insights into the significant role of single atom of the SAAs in catalytic reactions and can provide evidence for designing new SAAs with high-performance catalytic activities.

单原子催化剂（SAC），包括称为单原子合金（SAA）的金属-金属键合双金属催化剂，引起了人们对催化的极大兴趣。本文利用量子化学计算研究了单原子合金Au ₃₇ Pd _1的双金属金-钯（Au-Pd）模型上CO氧化反应的催化机理和键合分析。CO @ Au-Pd，O ₂ @ Au-Pd和CO / O ₂的分子几何结构和吸附物/底物的结合能识别@ Au-Pd配置。对于Au-Pd SAA，核-壳结构被证实是最稳定的结构，其中Pd原子更喜欢位于核位点。已经证实了从Pd原子到Au原子的电荷转移可以稳定结构。根据结合能和化学键合分析，CO和O _2都倾向于以低配位数结合到六价位的Pd原子上。确定了新的共吸附物质的形成，其中CO和O _2的垂直和平行桥联吸附在金-钯键上观察到。发现在Au-Pd SAA上进行CO氧化具有低能垒是可行的，并且遵循Langmuir-Hinshewood（LH）机理。我们的工作提供了SAA单原子在催化反应中的重要作用的见解，并可以为设计具有高性能催化活性的新SAA提供证据。