Optimizing Adsorption Energies of Reaction Products and Intermediates on Metal/Metal Oxide Catalysts to Achieve High Activity and Tunable Selectivity in Solid-Gas Phase Reactions
Siyuan Zhu, Ph.D. Candidate
Jie Liu, Ph.D., Advisor
Abstract: The solid-gas phase reactions, such as CO2 hydrogenation, the Fischer-Tropsh process, CO oxidation, and ammonia synthesis are one of the heterogenous catalytic reactions which have been emerged as a critical process in chemical and energy industries for a sustainable future. To design catalysts for solid-gas phase reactions, the Sabatier's principle is used that the relationship of the catalytic activity and adsorption energies of reactants, products or intermediates is a volcano curve. In this work, we first designed a two-temperature process to overcome high adsorption energy of the product, methanol, on indium oxide catalyst by photothermal desorption. Then, we developed a one-step combustion synthesis method and changed the composition in the rhodium-based catalyst support to tune the adsorption energy of reaction intermediate to achieve high CO selectivity. In the end, we used the same combustion method and optimized the CoMo bicatalyst composition to achieve high ammonia decomposition efficiency. One variable to be tuned in the catalyst composition limits the enhancement of catalytic activity. However, multiple variables to be tuned at the same time is impractical to analyze data and conclude it by human-being. With the simple synthesis method that we've developed for synthesizing bulk catalysts. It's promising and practical to provide training data for artificial intelligence to optimize the composition of earth-abundant metal catalysts to replace the noble metal catalysts in the future for the solid-gas phase reactions.