Generalized Bronsted-Evans-Polanyi relationships and descriptors for O-H bond cleavage of organic molecules on transition metal surfaces

Abstract

Periodic density functional theory (DFT) based calculations were used to explore the relationship between the activation energy corresponding to RO-H bond cleavage of organic compounds on catalytically active transition metal surfaces and other simpler quantities which can be used as descriptors. Taking data for methanol on various surfaces, several Brensted-Evans-Polanyi (BEP)-like relationships linking the activation energy barrier to the reaction energy, the adsorption energy of the reaction products or to the adsorption energy of an oxygen atom were explored. The general validity of these relationships has been explored by considering cases not included in the database used to extract the BEP relationships. For the more promising BEP relationship, the database for methanol was combined with results corresponding to O-H bond breaking of ethanol, formic acid and water on a sufficiently broad number of transition metal surfaces. This extended database provided a more general and statistically meaningful general BEP type relationship connecting the activation energy for the O-H bond breakage of general RO-H compounds on catalytic transition metal systems to the adsorption energy of the reaction products. Finally, a protocol is presented that allows one to determine good candidates for bond breakage of general RO-H compounds on metallic and bimetallic surfaces limiting the explicit calculation of the activation energy barriers to a few, previously detected, interesting cases only. (C) 2014 Elsevier Inc. All rights reserved.