Characteristic features of the d-band in electronic structure of transition metals are quite effective as descriptors of their catalytic activity toward oxygen reduction reaction (ORR). With the promise of graphene-based materials to replace precious metal catalysts, descriptors of their chemical activity are much needed. Here, a site-specific electronic descriptor is proposed based on the p (π) orbital occupancy and its contribution to electronic states at the Fermi level. Simple structural descriptors are identified, and a linear predictive model is developed to precisely estimate adsorption free energies of OH (ΔG ) at various sites of doped graphene, and it is demonstrated through prediction of the most optimal site for catalysis of ORR. These structural descriptors, essentially the number of ortho, meta, and para sites of N/B-doped graphene sheet, can be extended to other doped sp hybridized systems, and greatly reduce the computational effort in estimating ΔG and site-specific catalytic activity.

Using first principles approach, we investigate the catalytic activity of noble metal-free n-doped (C→B, O→N) hexagonal boron nitride (h-BN) monolayer for CO oxidation. To be mentioned CO adsorption ability, and hence the preferred Eiley-Rideal (ER) and Langmuir Hinshelwood (LH) mechanism for CO oxidation is dopant-dependent: CO is chemisorbed on O-doped h-BN (OBN) while it interacts physically with C-doped h-BN (CBN) surface. Even though both C and O doping create similar donor states below the Fermi level (E f ), the O doping results in larger bond length of O-B1 (one of the nearest B atom), out-of plane displacement of B1 atom and less positive charge on B1 atom, synergistically making this atom higher in activity. The presence of a pre-adsorbed O 2 molecule in both types of surfaces eliminates any chances of CO poisoning of the surface and CO oxidation prefers to proceed via ER mechanism with small activation barrier. The high values of Sabatier activities suggest doped h-BN surface to be superior to Au 55 and Pt 55 nanoclusters.In case of CO oxidation by means of LH mechanism, a stable O 2 ···CO intermediate is produced, which requires quite high barrier energy to break the O-O bond. However, the presence of a H 2 O molecule increases the activity of the catalyst and helps in catalytic CO de-

Using first-principles density functional theory calculations, we used a thin oxide overlayer, such as MgO, on a metal surface as an inverse catalyst for dioxygen reduction. Surface distortions in the oxide layer, combined with the tunneling of electron from the underneath metal, activated the adsorbed O 2 in the form of a superoxo or peroxo. On the other hand, the thin MgO overlayer readily prevents the π-back-bonding between CO and the metal surface, thereby efficiently mitigating the affinity of the metal surface for CO. The operating potential and overpotential for the oxygen reduction reaction (ORR) process have been estimated for various combinations of thin insulators and metals. The strongest binding intermediate in the overall reaction pathway influenced the overpotential. We show that for a Ag(100)-supported MgO surface, the ORR commences with a low overpotential, which is comparable to that of the Pt(111) surface. This suggests that an optimally chosen insulator−metal overlayer structure can yield a sharply tuned free energy profile for ORR.