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[Display omitted] • Small and uniform CeO 2 nanoparticles were prepared on Al 2 O 3 (CA-T) using a two-step incipient wetness impregnation method. • Pt single sites anchored to step sites of small CeO 2 entities within CA-T were more stable than those anchored to crystal surface of large CeO 2 particles on regular ceria-alumina. • The reactivity of CO adsorbed on Pt sites decreased by Pt cluster step sites ≈ Pt cluster terrace sites > Pt cluster corner sites ≫ Pt single sites on CeO 2. • Abundant Pt cluster step and terrace sites as well as rich Pt-CeO 2 interfaces facilitated the activated Pt/CA-T catalyst for efficient CO oxidation at low temperatures. In heterogeneous catalysis, the promotion of low temperature activity and enhancement of thermal stability simultaneously especially for precious metal catalysts is always highly demanded but very challenging. Herein we report a novel Pt catalyst on ceria-alumina (CeO 2 /Al 2 O 3) support (Pt/CA-T) engineered by a two-step ceria deposition strategy, exhibiting superior thermal stability and low-temperature carbon monoxide (CO) oxidation activity after activation. Pt single sites anchored to engineered CeO 2 edge sites are much more stable than that to CeO 2 (111) surface, and such stable single sites can be transformed into highly active Pt clusters for efficient low-temperature CO oxidation. Active site identification indicates that the CO oxidation activity of different Pt sites follows such sequence: Pt cluster step sites ≈ Pt cluster terrace sites > Pt cluster corner sites ≫ Pt single sites on CeO 2. The excellent low temperature activity of activated Pt/CA-T catalyst for CO oxidation is associated with its abundant Pt cluster step and terrace sites as well as rich Pt-CeO 2 interfaces, which facilitate the adsorption of active CO species and superior oxygen activation/transfer ability. The present study provides new insights into the structure–activity relationship of Pt-CeO 2 -Al 2 O 3 catalyst, which can also guide the preparation of other highly robust supported catalysts for important industrial applications. [ABSTRACT FROM AUTHOR]

Understanding the nature of active sites on metal oxide catalysts in the selective catalytic reduction (SCR) of NO by NH 3 (NH 3 -SCR) is a crucial prerequisite for the development of novel efficient NH 3 -SCR catalysts. In this work, two CeO 2 -based SCR catalyst systems with diverse acidic metal oxides-CeO 2 interfaces, i.e., Nb 2 O 5 -CeO 2 (Nb 2 O 5 /CeO 2 and CeO 2 /Nb 2 O 5) and WO 3 -CeO 2 (WO 3 /CeO 2 and CeO 2 /WO 3), were prepared and used to reveal the relationship between NH 3 -SCR activity and surface acidity/redox properties. In combination with the results of the NH 3 -SCR activity test and various characterizations, it was found that the NH 3 -SCR performance of Nb 2 O 5 -CeO 2 and WO 3 -CeO 2 catalysts was highly dependent on the strong interactions between the redox component (CeO 2) and acidic component (Nb 2 O 5 or WO 3), as well as the amount of paired redox-acid sites. From a quantitative perspective, an activity-surface acidity/redox property relationship was proposed. For both Nb 2 O 5 -CeO 2 and WO 3 -CeO 2 catalysts systems operated at the more concerned low-temperature range (200 °C), the NH 3 -SCR activity in low NO x conversion region (< 40%) was mainly dominated by the surface acidity of catalysts, while the NH 3 -SCR activity in high NO x conversion region (> 40%) was more determined by redox properties. [Display omitted] • Nb 2 O 5 -CeO 2 and WO 3 -CeO 2 catalysts with tuned redox-acid property were synthesized. • Paired redox-acid sites formed through strong interaction between Nb 2 O 5 /WO 3 and CeO 2. • NH 3 -SCR activity was well controlled by the paired redox-acid sites. • Surface acidity and redox property were investigated from a quantitative perspective. • A clear surface acidity/redox property-activity relationship was established. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel hybrid strategy is employed to design catalysts with superior K resistance. • The main reason for CeMn deactivation is cut-off of L-H mechanism resulting from the formation of stable nitrates. • The addition of ZSM-5 can re-activate the inert nitrates. • Alkali metals poisoned catalysts can be regenerated by ZSM-5 hybridization. The application of cerium-manganese oxides (CeMn) in controlling exhaust gas from biomass combustion is greatly inhibited due to poor resistance to alkali metals. Herein, we report a smart strategy to circumvent the K poisoning problem of CeMn by physically coupling with ZSM-5, which exhibited almost no activity loss even under a high loading of 2 wt % K 2 O. Results showed that in contrast to the conventionally believed disturbance of redox property and reduction of acid sites, the dominant effect from K loading on the deactivation of CeMn catalysts lies on the formation of chemically inert nitrates, which significantly restrains the reaction cycle via Langmuir-Hinshelwood route. With ZSM-5 hybridization, the stable nitrates over CeMn can be facilely activated and consumed by NH 4 + species introduced by ZSM-5, thus transforming poisoning sites into active sites and ensuring superior catalytic performance. The study presenting here not only provides an efficient strategy for fabricating NH 3 -SCR catalysts with superior K resistance but also sheds new light on the deactivation mechanism of K over CeMn catalysts. [ABSTRACT FROM AUTHOR]