Search

Ag catalysts supported on cobalt‐aluminum hydrotalcite derivative (CoAlO) nanosheet for CO oxidation are reported. A facile pre‐reduction treatment on reducible CoAlO support was employed to construct more oxygen vacancies for anchoring Ag sites to tune metal‐support interactions (MSI) and improve metal dispersion. The results show that directly loading Ag on CoAlO (Ag/CoAlO) can significantly promote the generation of active oxygen species by three times. Pre‐reduction of CoAlO enhances MSI of the Ag catalyst (Ag/CoAlO‐R), which further enlarges quantity of active oxygen species. Besides, the kinetic results demonstrate that compared with Ag/CoAlO, Ag/CoAlO‐R shows the additional advantages of the lower activation energy, the higher intrinsic activity of Ag sites, and especially the decreased reaction order of O2 from 0.20 to 0. The latter one indicates that enhancing MSI can readily activate gaseous oxygen at the interface of Ag and CoAlO, and the reaction mechanism obeys a typical Mars‐van Krevelen route. [ABSTRACT FROM AUTHOR]

• The kinetic model of crystal planes of CeO 2 is established for soot oxidation. • The kinetic model is based on the distributed activation energy model. • (1 0 0) planes of CeO 2 exhibit the low E a and high TOF in soot oxidation. • Abundant exposed (1 0 0) planes on CeO 2 nanocubes induce the high soot oxidation activity. Soot oxidation is a triple-phase reaction system involved in solid soot, solid catalyst and gaseous oxidant, which makes its kinetic behavior difficult to be determined. Herein, we report the kinetic behavior of crystal planes on the CeO 2 catalysts with various morphologies for soot oxidation. We establish a kinetic model of crystal planes of CeO 2 in soot oxidation by means of the distributed activation energy model (DAEM). Through analyzing the distribution function of apparent activation energies (f (E a)) under loose contact condition, we discover that the E a of the exposed (1 0 0), (1 1 1) planes and non-catalytic gaseous O 2 on soot oxidation distributes in the range of 60–100, 100–150, and 150–250 kJ mol−1, respectively. Our findings show that compared with other catalysts, CeO 2 nanocubes exhibit the higher intrinsic activity (turnover frequency, TOF) under loose contact condition, because of the higher f (E a) value of abundant active exposed (1 0 0) planes located at the lower E a range. Our work develops a methodology of kinetic analysis to investigate the soot oxidation reaction, which could be potentially extended to other complex oxidation systems. [ABSTRACT FROM AUTHOR]