123rd General Meeting of the KCS

Type Symposium
Area Physical Chemistry Approaches in Energy and Environmental Materials
Room No. Room 401+402
Time FRI 16:20-16:40
Code PHYS3-6
Subject A descriptor based approach to find promising catalysts – Methane oxidation on transition-metal surfaces as an example
Authors Jong Suk Yoo
Chemical Engineering, University of Seoul, Korea
Abstract In this talk, I would like to discuss how density functional theory and microkinetic modeling can be employed to investigate CH4 oxidation to CO, CO2, CH2O, and CH3OH on Pd(111) under mildly oxidizing conditions. Although our energetic analysis indicates that the metallic site on Pd(111) is more active than O* and OH* on the Pd surface for C–H bond activation, our microkinetic analysis indicates that the metallic site produces mostly CO, whereas the O* site produces mostly CH2O. In addition, we show that the product selectivity can change significantly depending on the pressures of the products (CO, CO2, CH2O, and CH3OH). Increasing the product pressures leads to the promotion of CO2 production, because CO oxidation becomes more active than CH4 oxidation. We then extend the study to other FCC(111) surfaces by incorporating the linear scaling relations in the mean-field microkinetic model. We find that most transition-metal surfaces cannot effectively activate CH4 under the reaction conditions employed. We find that the kinetics of CH4 oxidation to CO, CO2, CH2O, and CH3OH can be described generally as a function of two descriptors, enabling identification of the most promising catalyst surface for selective production of the desired product.
E-mail jsyoo0927@gmail.com