Comparative study of the electrocatalytic N2 reduction property of a Cu4 cluster with μ2-/μ3-OH and a Cu2 complex with μ2-OH

Abstract

Using the atomic precisely structurally characterized clusters as electrocatalysts can provide some possible structure information about the active intermediate during the electrocatalytic N2 reduction reaction (NRR) process. A Cu4 cluster, named [(bpy)4Cu4(C10H8SO3)4(OH)4]•4H2O (1), has been synthesized and fully characterized by IR, SXRD, XPS, EPR, et al. Single crystal structural analysis reveals that the core structure of the cluster has a step-scheme conformation with two μ2-OH and two μ3-OH groups. Electro-catalysis studies of this cluster show that it can achieve a highest NH3 yield of 2.18 μg h−1 mg−1 and a FE of 0.97 % at −0.6 V. The excellent NRR performance may be attributable to the additional μ3-OH groups, based on the contrastively study of the other electrocatalysts of the Cu powder and the Cu2 complex, named [(μ2-OH)(μ2-Cl)(bpy)2Cu2Cl2] (2), with one μ2-OH group in its structure. This work provides some structure information about the possible active sites during the NRR process and inspires us to develop new cluster as efficient electrocatalysts for advancing sustainable NH3 production. Using the atomic precisely structurally characterized clusters as electrocatalysts can provide some possible structure information about the active intermediate during the electrocatalytic N2 reduction reaction (NRR) process. A Cu4 cluster, named [(bpy)4Cu4(C10H8SO3)4(OH)4]•4H2O (1), has been synthesized and fully characterized by IR, SXRD, XPS, EPR, et al. Single crystal structural analysis reveals that the core structure of the cluster has a step-scheme conformation with two μ2-OH and two μ3-OH groups. Electro-catalysis studies of this cluster show that it can achieve a highest NH3 yield of 2.18 μg h−1 mg−1 and a FE of 0.97 % at −0.6 V. The excellent NRR performance may be attributable to the additional μ3-OH groups, based on the contrastively study of the other electrocatalysts of the Cu powder and the Cu2 complex, named [(μ2-OH)(μ2-Cl)(bpy)2Cu2Cl2] (2), with one μ2-OH group in its structure. This work provides some structure information about the possible active sites during the NRR process and inspires us to develop new cluster as efficient electrocatalysts for advancing sustainable NH3 production.