The request for both high catalytic selectivity and high catalytic activity is rather challenging, particularly for catalysis systems with the primary and side reactions having comparable energy barriers. Here in this study, we simultaneously optimized the selectivity and activity for acetylene semi-hydrogenation by rationally and continuously varying the doping ratio of Zn atoms on the surface of Pd particles in Pd/ZnO catalysts. In the reaction temperature range of 40–200 °C, the conversion of acetylene was close to ∼100%, and the selectivity for ethylene exceeded 90% (the highest ethylene selectivity, ∼98%). Experimental characterization and density functional theory calculations revealed that the Zn promoter could alter the catalyst's potential energy surface, resulting in a “confinement” effect, which effectively improves the selectivity yet without significantly impairing the catalytic activity. The mismatched impacts on activity and selectivity resulting from continuous and controllable alteration in the catalyst structure provide a promising parameter space within which the two aspects could both be optimized.

中文翻译：

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通过 Pd 纳米颗粒表面感应势垒的限制效应规避活性-选择性权衡

对高催化选择性和高催化活性的要求相当具有挑战性，特别是对于主反应和副反应具有相当能垒的催化系统。在本研究中，我们通过合理、连续地改变Pd/ZnO催化剂中Pd颗粒表面Zn原子的掺杂比例，同时优化乙炔半加氢的选择性和活性。在40~200℃的反应温度范围内，乙炔转化率接近~100%，乙烯选择性超过90%（乙烯选择性最高~98%）。实验表征和密度泛函理论计算表明，Zn助剂可以改变催化剂的势能面，产生“限域”效应，有效提高选择性，但不会显着损害催化活性。催化剂结构的连续可控改变对活性和选择性的不匹配影响提供了一个有希望的参数空间，在该空间内这两个方面都可以得到优化。