Sequencing the CuOx active species for CO preferential oxidation at low-temperature over CeO2-CuO composite catalysts

Composites are frequently uncovered to show superior catalytic performance at mild conditions for a variety of emerging applications in energy and environment, while identity of low-temperature active species and their role remains elusive. Herein, we took CeO2-CuO as a prototypical composite to sequence the active species respon-sible for the superior catalytic performance of CO preferential oxidation at low-temperature. Through data an-alyses of structure, reducible ability, adsorption/desorption behaviors of oxygen species, and in situ spectroscopic features, highly dispersed CuOx species are experimentally identified to be the active centers that dominate the catalytic performance as represented by a redox temperature below 150 degrees C. The methodology of elevating the concentration of active species is further demonstrated by increasing annealing temperature as well as by tuning the dispersion of CeO2 and CuO components that controls Ce3+ content in composite. These findings may provide hints of creating highly concentrated active sites when designing advanced composites for low -temperature catalytic applications.

Automated summary

In this study, highly dispersed CuOx species in CeO2-CuO composite were identified as the active centers for the superior catalytic performance of CO preferential oxidation at low temperatures. The concentration of active species can be increased by tuning the dispersion of CeO2 and CuO components, providing new insights for designing advanced composites for low-temperature catalytic applications.