Comparative activity and hydrothermal stability of FeOx- and CeO2-doped Pt-based catalysts for eliminating diesel emissions

Constructing a Pt/YMn2O5 Interface to Form Multiple Active Centers to Improve the Hydrothermal Stability of NO Oxidation

“…O 2 -TPD (Figure ) was used to further illustrate the presence of abundant O v in Pt/YMO-LA-a. According to previous references, the desorption peak of O 2 -TPD can be divided into three parts: weakly adsorbed oxygen species, denoted O α1 (80–150 °C), relatively strongly adsorbed oxygen species, denoted O α2 (150–230 °C), and the oxygen species absorbed by O v noted as O β (230–410 °C). , …”

“…According to previous references, the desorption peak of O 2 -TPD can be divided into three parts: weakly adsorbed oxygen species, denoted O α1 (80−150 °C), relatively strongly adsorbed oxygen species, denoted O α2 (150−230 °C), and the oxygen species absorbed by O v noted as O β (230−410 °C). 20,32 By the semiquantitative analysis of the three peak areas of O 2 -TPD (Figure 7), we can find that the magnitude of the relative area of O β corresponds to the results of NO activity. For fresh catalysts, the total oxygen desorption area was in the order Pt/LA-f > Pt/YMO-LA-f > Pt/YMO-f, but it was in the order Pt/YMO-LA-a > Pt/LA-a > Pt/YMO-a after hydrothermal aging.…”

“…The LA had the following texture properties: surface area (147.8 m 2 g −1 ) and total pore volume (0.49 cm 3 g −1 ). Then, 1 wt % Pt was impregnated on LA, LA-YMO, and YMO supports according to a facile wet impregnation method previously reported, 32 and fresh samples were obtained by drying at 60 °C for 1 day and calcining at 550 °C for 180 min. The fresh samples were labeled Pt/LA-f, Pt/YMO-LA-f, and Pt/YMO-f, respectively.…”

“…For Pt/YMO-LA-f, bidentate nitrate (1619 cm −1 ) and bridged nitrate (1590 cm −1 ) were relatively weak, and so monodentate nitrites (1561 cm −1 ) were considered the main intermediate, which shows that it conformed to the Langmuir−Hinshelwood (L−H) reaction mechanism. 32 At low temperatures, O 2 molecules and NO molecules compete for adsorption at the active sites of the catalyst. Then, as the temperature is increased, the adsorbed oxygen is activated and reacts with the NO adsorbed on Pt to form intermediates.…”

A Review on the Impact of SO2 on the Oxidation of NO, Hydrocarbons, and CO in Diesel Emission Control Catalysis

“…As presented in the layout of current diesel exhaust aftertreatment system architecture (Figure a): DOC meets the exhaust first, closely followed by DPF, combined with downstream coupled SCR and ASC assembles. Within this working architecture, DOC functions to (1) oxidize unburned HCs and CO into CO 2 or/and H 2 O, and especially a portion of NO to NO 2 with excess air input; and (2) boost PM and NO x purification efficiency in downstream working cells by generating heat and NO 2 . ,,− The principal role of DPF is to trap soot while at much lower temperatures when O 2 dose is unable to combust soot, the NO 2 generated over DOC acts as an oxidant (called “passive” regeneration). As a relatively high temperature is required for DPF to enable soot combustion, DOCs also involve heating the exhaust by exothermic oxidation of HCs (either coming from exhaust or additionally injected fuel).…”