- Xiang Wang, Cummins Technical Center, Columbus, Indiana
Catalytic CO2 conversion to energy carriers and intermediates is of utmost importance to energy and environmental goals. However, the lack of fundamental understanding of the reaction mechanism renders designing a selective catalyst inefficient. The speaker will describe operando experiments in which transmission Fourier transform infrared/steady-state isotopic transient kinetic analyses were carried out to determine the correlation between the kinetics of product formation and those of surface species conversion during CO2 reduction over Pd/Al2O3 catalysts. The rate-determining step for CO formation was determined to be the conversion of adsorbed formate; the rate-determining step for CH4 formation was determined to be the hydrogenation of adsorbed carbonyl. The balance of the hydrogenation kinetics between adsorbed formates and carbonyls governs the selectivity to CH4 and CO. Catalysts that were designed based on that knowledge achieved high selectivity to desired products.