Ozone Decomposition on Defective Graphene: Insights from Modeling
Heng Zhang, Jin Yong Lee, Hongguang Liu
Abstract
We propose via first-principles calculations that graphene tailored with specific structural or foreign-atom defects can be used as catalysts for O3 decomposition. Compared to the pristine graphene, we show that introduction of thermodynamically stable surface defects, that is, Stone-Wales, 555–777 divacancy or nitrogen atoms to graphene, can drastically lower the chemisorption energy barrier of O3. The ozonides once formed can evolve into epoxide or ketone-like intermediate structures on graphene, which assist in the sustainable conversion of O3 to O2. The minimal energy needed to complete the O3 decomposition cycle on different graphene substrates has the order of E555–777 (0.22 eV) < EN-doping (0.33 eV) < EStone-Wales (0.61 eV) < Epristine graphene (1.08 eV). As two most promising catalysts, 555–777 divacant and N-doped graphene shows a clear adsorption selectivity to O3 under the ambient conditions. N-doped graphene outperforms 555–777 divacant graphene at the stage of physisorption in that the former catalyst separates O3 from the ambient gases by a much larger adsorption energy. These results and conclusions are a pivotal and necessary step that should stimulate both the proof-of-principle experiments and the computational search of metal-free catalysts for O3 decomposition.