Bond-Energy-Integrated Coordination Number: An Accurate Descriptor for Transition-Metal Catalysts

Heterogeneous catalysis on metal is generally governed by the chemisorption on surface sites. Unveiling the nature of chemisorption on a metal is of crucial importance on discovering catalytic mechanism and designing optimal catalysts. However, a simple and efficient theoretical model is still lacking on simulating the chemisorption. Herein, we demonstrate that bond-energy-integrated d-orbitalwise coordination number (CNd) is a reasonable descriptor for the chemisorption on metals. Compared with other available descriptors, our descriptor has a direct physical relationship with the adsorption energy on metals. It considers the bond energy between the active site and its neighboring sites, as well as the orbital interaction between the adsorbate and surface atom. Consequently, the value of CNd of clean metal surface directly reflects the chemisorption strength of different active sites, and its accuracy is much superior to other descriptors. The theoretical prediction based on our model is consistent with experimental results and universal for heterogeneous catalysis on various metals. Our study provides an explicit guideline for engineering heterogeneous catalysts.