The single-atom catalysts (SACs) with the maximum metal utilization efficiency exhibits the advantage of high ethylene selectivity compared with the cluster catalyst in the acetylene semi-hydrogenation reaction, however, the SACs also possess the disadvantages of poor activity and high-temperature stability. Thus, maintaining high reactivity and stability while achieving high ethylene selectivity faces a challenge. The coordination environment of the first metal atom is reasonably adjusted by coordinating with the second adjacent metal atom, which provides the possibility of stimulating the intrinsic reactivity of SACs and maintaining the atomic properties unchanged during the reaction. Here, we prepared Pd-Cu/AlO catalysts with palladium single-atom species (Pd) and copper cluster species (Cu) loaded on AlO support by combining “anchoring” and “site isolation”, which effectively prevented the Pd transition to Pd cluster species (Pd) during the reaction process while improving the activity of Pd. The reaction evaluation results revealed that the activity of the Pd-Cu/AlO catalyst increased by 60 % compared with the Pd/AlO catalyst, and the stabilization time of ethylene selectivity (83 %) of Pd-Cu/AlO catalyst increased by > 100 h when the same conversion for both catalysts. The aberration-corrected high-angle annular dark-field scanning transmission electron microscopic (AC-HAADF-STEM), Diffuse reflectance Fourier transform infrared spectroscopy of CO adsorption (CO-DRIFTS) and X-ray photoelectron spectroscopy (XPS) showed that the “synergistic effect” of Cu and Pd is the main reason for the increase of reactivity, and the “site isolation” effect of Cu is a key factor in preventing the transition of Pd to Pd. This method provides new research ideas for improving the activity of SAC and inhibiting the agglomeration of active centers.

中文翻译：

---

寸簇稳定Pd1单原子催化剂高效乙炔半加氢


金属利用效率最高的单原子催化剂（SAC）在乙炔半加氢反应中与簇催化剂相比表现出乙烯选择性高的优点，但也存在活性和高温稳定性较差的缺点。因此，在实现高乙烯选择性的同时保持高反应活性和稳定性面临着挑战。通过与相邻的第二金属原子配位，合理调整第一金属原子的配位环境，这为激发SACs的固有反应性并在反应过程中保持原子性质不变提供了可能。在这里，我们通过“锚定”和“位点隔离”相结合的方式，将钯单原子物种（Pd）和铜簇物种（Cu）负载在Al2O3载体上制备了Pd-Cu/Al2O3催化剂，有效阻止了Pd向Pd簇合物的转变反应过程中增加Pd的活性，同时提高Pd的活性。反应评价结果表明，Pd-Cu/Al2O3催化剂的活性较Pd/Al2O3催化剂提高了60%，乙烯选择性（83%）的稳定时间提高了>100 h 当两种催化剂的转化率相同时。像差校正高角度环形暗场扫描透射电子显微镜（AC-HAADF-STEM）、CO吸附漫反射傅里叶变换红外光谱（CO-DRIFTS）和X射线光电子能谱（XPS）表明“ Cu和Pd的“协同效应”是反应活性增加的主要原因，而Cu的“位点隔离”效应是阻止Pd向Pd转变的关键因素。 该方法为提高SAC活性、抑制活性中心团聚提供了新的研究思路。