Electrochemical hydrogenation of acetonitrile based on well-developed proton exchange membrane electrolyzers holds great promise for practical production of ethylamine. However, the local acidic condition of proton exchange membrane results in severe competitive proton reduction reaction and poor selection toward acetonitrile hydrogenation. Herein, we conduct a systematic study to screen various metallic catalysts and discover Pd/C exhibits a 43.8% ethylamine Faradaic efficiency at the current density of 200 mA cm⁻² with a specific production rate of 2912.5 mmol g⁻¹ h⁻¹, which is about an order of magnitude higher than the other screened metal catalysts. Operando characterizations indicate the in-situ formed PdH_x is the active centers for catalytic reaction and the adsorption strength of the *MeCH₂NH₂ intermediate dictates the catalytic selectivity. More importantly, the theoretical analysis reveals a classic d-band mediated volcano curve to describe the relation between the electronic structures of catalysts and activity, which could provide valuable insights for designing more effective catalysts for electrochemical hydrogenation reactions and beyond.

基于成熟的质子交换膜电解槽的乙腈电化学加氢技术在乙胺的实际生产中具有广阔的前景。然而，质子交换膜的局部酸性条件导致激烈的竞争性质子还原反应以及对乙腈加氢的不良选择。在此，我们进行了系统研究，筛选了各种金属催化剂，发现Pd/C在200 mA cm ^-2的电流密度下表现出43.8%的乙胺法拉第效率，比产率为2912.5 mmol g ^-1 h ^-1 ，其中比其他筛选的金属催化剂高大约一个数量级。操作表征表明原位形成的PdH _x是催化反应的活性中心，并且*MeCH ₂ NH ₂中间体的吸附强度决定了催化选择性。更重要的是，理论分析揭示了经典的 d 带介导的火山曲线来描述催化剂的电子结构和活性之间的关系，这可以为设计更有效的电化学氢化反应等催化剂提供有价值的见解。