Unraveling Electronic Trends in O* and OH* Surface Adsorption in the MO<sub>2</sub> Transition-Metal Oxide Series
Benjamin M. Comer, Jiang Li, Frank Abild‐Pedersen, Michal Bajdich, Kirsten T. Winther
Abstract
Understanding the bond strength of O* and OH* intermediates to metal-oxide surfaces is key to predicting the catalytic activity in oxygen-based electrochemistry. In this work, we uncover highly non-linear trends in O* and OH* adsorption energies across the 3d, 4d, and 5d series of MO2 transition-metal (TM) oxide surfaces computed within Hubbard-U corrected density functional theory (DFT + U). Investigating the electronic structure with crystal orbital Hamiltonian populations (COHP) of the relevant metal–oxygen bonds reveals that the spin-dependent coupling strength between metal-d and oxygen-2p atomic orbitals together with the extent of filling of bonding and anti-bonding orbitals are the primary contributors to the adsorption energy. Importantly, we show that the integrated COHP obtained purely from bulk calculations is a highly accurate descriptor for surface adsorption energetics that captures trends across the group 5–12 TM oxide series within 0.19–0.36 eV. Our results suggest a pathway to prediction of adsorption energies for an arbitrary metal–ligand catalyst system.