Metal and ligand modification modulates the electrocatalytic HER, OER, and ORR activity of 2D conductive metal-organic frameworks

It is highly desirable to design efficient and stable hydrogen evolution reaction (HER) and oxygen evolution/reduction reaction (OER/ORR) electrocatalysts for the development of renewable energy technologies. Herein, density functional theory (DFT) calculations were conducted to systematically investigate a series of TMNxO4−x-HTT (TM = Fe, Co, Ni, Ru, Rh, Pd, Ir and Pt; HTT = hexahydroxy tetraazanaphthotetraphene) analogs of two-dimensional (2D) conductive metal-organic frameworks (MOFs) as potential electrocatalysts for the HER, OER and ORR. The thermodynamic and electrochemical stability simulations suggest that these designed catalysts are stable. Remarkably, CoO4-HTT, RhN3O1-HTT and IrN3O1-HTT are predicted to be the most promising catalysts for the HER, OER and ORR, respectively, surpassing the catalytic activity of corresponding benchmark catalysts. The volcano plots were established based on the scaling relationship of adsorption Gibbs free energy of intermediates. The results reveal that regulating combinations of metal active centers and local coordination environments could effectively balance the interaction strength between intermediates and catalysts, thus achieving optimal catalytic activity. Our findings not only opt for the promising HER/OER/ORR electrocatalysts but also guide the design of efficient electrocatalysts based on 2D MOFs materials.