Vacancy-defects turn off conjugated π bond shield activated catalytic molecular adsorption process

Abstract

Non-metal carbon materials have been widely utilized in diversified electrocatalytic reaction in virtue of property advantages. And the defective structure has greatly affected the physicochemical properties. Thus, it is of great significance to understand the mechanism of defective effect. Herein, we constructed graphene structural model to in-depth understand the electronic characteristics of vacancy defect sites and further comprehend the molecular interaction during the adsorption process. Our results indicate that the vacancy defect can effectively turn off conjugated π bond shield and form defect state, including π state and σ state. According to the fragment orbital analysis, due to the conjugated π bond shielding effect of perfect graphene, it cannot bond to nonpolar molecule. Even polar molecules, it needs to induce polar π defect on the surface of perfect graphene firstly. However, whether it's polar or nonpolar molecular, it can easily track coupling with the defect sites where the shield is turned on. The findings point out a new avenue to understand the catalytic behavior for carbon materials.