Constructing 3D hierarchical MOFs nanospheres for oxygen evolution from high-throughput calculations

Abstract

In order to realize outstanding electrochemical performance in oxygen evolution reactions (OER), it is important to construct 3D hierarchical nanospheres consisting of 2D bimetal metal–organic framework (MOF) nanosheets. Based on high-throughput density-functional theory (DFT) calculations, we chose Ni and V as central ions and prepared Ni-V bimetal MOFs nanospheres (NiV-MNs) assembled from ultrathin 2D MOFs nanosheets through a simple one-step solvothermal method. So far, V-based ultrathin 2D MOFs have been firstly reported. Gradient experiments demonstrated that NiV-MNs shows the best catalytic activity when the amount of Ni is equal to that of V (denoted as Ni1V1-MNs). The Ni1V1-MNs can deliver a high current density of 50 mA·cm−2 at a low over-potential of 370 mV in alkaline condition even after 10000 s continuous catalytic testing. Coincidentally, the DFT calculations further confirmed that the ΔG of Ni1V1-MNs is much lower compared with Ni1V2-MNs and Ni2V1-MNs. Based upon the experimental results and DFT calculations, we propose that the better performance of Ni1V1-MNs should be attributed to the grater intrinsic activity of Ni and the coupling effect between Ni and V, as they are crucial for tuning the electrochemical activity.