Ceria morphology-dependent Pd-CeO2 interaction and catalysis in CO2 hydrogenation into formate

Several Pd catalysts supported on CeO2 with different morphologies (i.e. CeO2 rods (r-CeO2), cubes (c-CeO2) and polyhedra (p-CeO2)) were tested for the CO2 hydrogenation into formate. Remarkable morphology - dependent Pd-CeO2 interaction was observed, which was related to the oxygen vacancies in the CeO2. The r-CeO2 with the highest concentration of oxygen vacancy resulted in smaller Pd particles and more positively-charged Pd species in the Pd/r-CeO2 catalyst. The best performance was obtained over the Pd/p-CeO2 catalyst, giving a turnover frequency of 746 h(-1) at 40 degrees C. The enhanced activity was due to the highest content of metallic Pd species in the catalyst, which was responsible for the facile activation of H-2. Moreover, in situ spectroscopic results revealed that the hydrogenation of the carbonaceous intermediates was the rate - determining step. This work demonstrates oxide morphology engineering as a powerful strategy in developing efficient Pd - based catalysts for CO2 hydrogenation. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

Pd catalysts supported on CeO2 with different morphologies showed morphology-dependent interaction, with the Pd/p-CeO2 catalyst exhibiting the best performance due to the highest content of metallic Pd species. This study demonstrates the effectiveness of oxide morphology engineering in developing efficient Pd-based catalysts for CO2 hydrogenation.