Effect of oxygen vacancy on the oxidation of toluene by ozone over Ag-Ce catalysts at low temperature

Unlocking High-Efficiency Methane Oxidation with Bimetallic Pd–Ce Catalysts under Zeolite Confinement

“…For PdCe 0.4 @S-1, a band at 594 cm –1 corresponding to a defect-induced (D) vibration mode was detected and is generally ascribed to oxygen vacancy sites in CeO 2 . , EPR studies confirmed the presence of bulk oxygen vacancy defects in the PdCe 0.4 @S-1 catalysts. As shown in Figure c, a symmetrical signal at g = 2.004 ascribed to unpaired electrons in oxygen vacancies was visualized in the spectrum of PdCe 0.4 @S-1. , The existence of oxygen vacancies is beneficial for the activation of gaseous O 2 molecules to generate reactive oxygen species capable of cleaving C–H bonds in CH 4 . − Accordingly, O 2 -TPD measurements were conducted to investigate the oxygen properties of PdCe 0.4 @S-1 and related catalysts. Indeed, in the O 2 -TPD profiles in Figure d, more intense oxygen desorption peaks were recorded at ca.…”

“…As shown in Figure 4c, a symmetrical signal at g = 2.004 ascribed to unpaired electrons in oxygen vacancies was visualized in the spectrum of PdCe 0.4 @S-1. 47,48 The existence of oxygen vacancies is beneficial for the activation of gaseous O 2 molecules to generate reactive oxygen species capable of cleaving C−H bonds in CH 4 . 49−51 Accordingly, O 2 -TPD measurements were conducted to investigate the oxygen properties of PdCe 0.4 @S-1 and related catalysts.…”

Engineering the Crystal Facet of Monoclinic NiO for Efficient Catalytic Ozonation of Toluene

“…For comparison, noble/non-noble metal oxide catalysts known to exhibit excellent performance for CTO at room temperature are listed in Table S3. Both PtMnO x , being the most frequently reported metal oxide catalyst, and AgCeO x , being the best active metal oxide catalyst reported to date, were selected for comparison under the same experimental conditions. The toluene conversion, CO x selectivity, and ozone conversion of NiO-(111) after reaction for 120 min reached ∼100, ∼55, and ∼100%, respectively, which were far superior to those of the PtMnO x and AgCeO x catalysts (Figure a–c).…”

Fabricating Uniform TiO2–CeO2 Solid Solution Supported Pd Catalysts by an In Situ Capture Strategy for Low-Temperature CO Oxidation

“…36 In the H 2 -TPR profiles (Figure 5b), peaks below 250 °C can be assigned to the reduction of PdO x species and surface reactive oxygen of supports interacted with Pd due to the hydrogen spillover effect, while peaks at 250−450 °C and around 800 °C can be attributed to the reduction of surface and bulk lattice oxygen of ceria, respectively. 28,38 Although a larger reduction peak arose around 800 °C for PTC-iC, which indicates the enhanced mobility of bulk lattice oxygen due to introduction of Ti ions into CeO 2 crystal lattice, the reducibility of surface active species plays a more important role in the low-temperature CO catalytic oxidation. In view of this, within the low-temperature region of 40−450 °C, the PTC-iC shows a larger H 2 consumption peak area that is 1.3 times that of PTC (Table S3), and a peak around 200 °C for PTC-iC shifts to a lower temperature compared to that for PTC, suggesting the former has more surface active oxygen species, which can be ascribed to the strong interaction between the well-dispersed Pd species and surface oxygen, as well as the improved mobility of lattice oxygen due to the formation of a uniform TiO 2 −CeO 2 solid solution.…”