Pairing d‐Band Center of Metal Sites with π‐Orbital of Alkynes for Efficient Electrocatalytic Alkyne Semi‐Hydrogenation
Jinjin Li, Ying Guo, Siyu Chang, Jin Lin, You Wang, Zhenpeng Liu, Yafei Wu, Jian Zhang
Abstract
Abstract Electrocatalytic alkyne semi‐hydrogenation has attracted ever‐growing attention as a promising alternative to traditional thermocatalytic hydrogenation. However, the correlation between the structure of active sites and electrocatalytic performance still remains elusive. Herein, the energy difference (∆ε) between the d‐band center of metal sites and π orbital of alkynes as a key descriptor for correlating the intrinsic electrocatalytic activity is reported. With two‐dimensional conductive metal organic frameworks as the model electrocatalysts, theoretical and experimental investigations reveal that the decreased ∆ε induces the strengthened d–π orbitals interaction, which thus enhances acetylene π‐adsorption and accelerates subsequent hydrogenation kinetics. As a result, Cu 3 (HITP) 2 featuring the smallest ∆ε (0.10 eV) delivers the highest turnover frequency of 0.36 s −1 , which is about 124 times higher than 2.9 × 10 −3 s −1 for Co 3 (HITP) 2 with the largest ∆ε of 2.71 eV. Meanwhile, Cu 3 (HITP) 2 presents a high ethylene partial current density of −124 mA cm −2 and a large ethylene Faradaic efficiency of 99.3% at −0.9 V versus RHE. This work will spark the rapid exploration of high‐activity alkyne semi‐hydrogenation catalysts.