Identifying the critical surface descriptors responsible for the appearance of negative slopes in the adsorption energy scaling relationships

TL;DR

This study investigates the factors causing negative slopes in adsorption energy scaling relationships across various bimetallic surfaces, highlighting the roles of surface descriptors like d-band center and magnetic moment.

Contribution

It introduces a multi-descriptor model explaining the occurrence of negative slopes in adsorption energy scaling relations beyond traditional single-descriptor approaches.

Findings

Positive slopes only for O vs N and F

Negative slopes dominate other element pairs

Surface descriptors like d-band center influence slope sign

Abstract

Adsorption energy scaling relationships have now developed beyond their original form, which was more targeted towards the optimization of catalytic sites and the reduction of computational costs in simulations. The recent surge of interest in the adsorption energy scaling relations is to explore the surfaces beyond the transition metals (TMs) as well as reactions involving complicated molecules. Breakdown of such scaling relationships leads to motivating the discovery of novel catalysts with enhanced capabilities. In this work, we report our extensive study on the linear scaling relation (LSR) between oxygen (O), a group VIA element with elements of neighbouring groups such as: Group IIIA (Boron (B), Aluminum (Al)), IVA (Carbon (C), Silicon (Si)), VA (Nitrogen(N),phosphorus(P)) and VIIA (Florine(F)) on magnetic bimetallic surfaces. We found that the slope is positive for only O versus N and F, remaining of the slopes are negative. The present model is based on multiple surface descriptors, particularly spin-averaged d-band center and the surface's magnetic moment, whereas the original scaling theory (Phys. Rev. Lett. 99, 016105 (2007)) was based on a single adsorbate descriptor: adsorbate valency.