Active Site Customizing of Metal-Organic Materials for Highly Efficient Oxygen Evolution

Elucidating the correlation of active sites and catalytic activity in multi-component metal-organic frameworks (MOFs) is key to understanding the mechanism of oxygen evolution reaction (OER), yet it remains nebulous. Herein, a direct pathway combining theoretical prediction with anchoring high-valence metals is proposed on MOFs to reveal the mechanism of the OER reaction. Density functional theory (DFT) predicts that the co-modulation by Mo and Co atoms can enhance the conductance of CoMOF and optimize the adsorption-free energies of the OER intermediates. Guided by the theoretical prediction, the Co-based MOFs grown on Ni foams are doped with high valence Mo, which is used as model catalysts for the quantitative study of the composition-dependent OER performance. With Co/Mo in the ratio of 5:1 for the highest OER activity (impressively overpotential of 324 mV at 100 mA cm^-2 and a Tafel slope of 96.07 mV dec^-1) and excellent stability (maintains for 200 h at 100 mA cm^-2), the catalysts in this work is superior to commercial benchmarks electrocatalysts (RuO₂/NF, 420 mV, 199.12 mV dec^-1). This work sheds light on the tailoring of the active sites of MOFs, which is highly correlated with the activity of the OER.