CO oxidation activity of Pt/CeO2 catalysts below 0ºC: Platinum loading effects

Reducing the operating temperature of oxidation catalysts is important for designing energy efficient processes, extending catalyst lifetime, and abating pollutants, especially in cold climates. Herein, high CO oxidation activity at sub-ambient temperatures is reported for Pt/CeO2 catalysts with high content of Pt in the form of dispersed Pt2+ and Pt4+ centers. Whereas the reference 1 wt%Pt catalyst was active for CO oxidation only above 100ᵒC, the 8 and 20 wt%Pt catalysts converted 60 and 90 % of CO, respectively, below 0ᵒC. Ionic platinum was shown to facilitate oxygen release from ceria and lower the light-off temperature of the reaction occurring through the Mars-van-Krevelen mechanism. However, the remarkable activity observed at sub-ambient temperatures for the ≥8 wt%Pt catalysts is proposed to involve O2 and CO reactants weakly adsorbed on PtOx clusters. The synergies between ionic platinum and nanostructured ceria reported in this work advance the knowledge-driven design of catalysts for low-temperature oxidation reactions

Estimation of the measurement range based on the criterion of permissible relative error

Рассмотрены вопросы, связанные с неразрушающим вихретоковым контролем неферромагнитных тонких пленок. Выявлен критерий оценки диапазона измерений различных типов вихретоковых преобразователей.Розглянуто питання, пов'язані з неруйнівним віхреструмовий контролем неферомагнітних тонких плівок. Виявлено критерій оцінки діапазону вимірювань різних типів віхреструмовий перетворювачів.The problems associated with non-destructive eddy current testing of non-ferromagnetic films and coatings. Revealed a measure of the measurement range of different types of eddy current probes