Soot oxidation performance with a HZSM-5 supported Ag nanoparticles catalyst and the characterization of Ag species

• Published in: RSC advances Vol. 7; no. 69; pp. 43789 - 43797
• Main Authors: Ruan, Hongcheng, Nishibori, Maiko, Uchiyama, Tomoki, Ninomiya, Kakeru, Kamitani, Kazutaka, Kato, Kazuo, Konishi, Yuko, Haensch, Alexander, Barsan, Nicolae, Weimar, Udo, Shimanoe, Kengo
• Format: Journal Article
• Language: English
• Published: 2017
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/C7RA06712G

A HZSM-5 supported Ag nanoparticles catalyst, which has a Si/Al ratio of 1500, is synthesized by a simple impregnation method for soot oxidation. Ultrafine Ag nanoparticles (NPs) of 1–2 nm in diameter were well dispersed and stable without any aggregation up to 800 °C, confirmed by high resolution scanning transmission electron microscopy, X-ray photoelectron spectroscopy, and high temperature X-ray diffraction. This catalyst exhibited high intrinsic soot oxidation activity and T max (peak temperature of DTA curves) values were 362 °C and 533 °C under tight contact and loose contact conditions, respectively. Furthermore, the physical and chemical states of Ag species before and during soot oxidation were examined by in situ X-ray absorption spectroscopy. Two kinds of Ag species (ZO − Ag + and Ag NPs) were found in this catalyst; they were reduced and crystallized after heating over 150 °C. The Ag NPs remained stable without any aggregation even after 800 °C, which means the Ag/HZSM-5 catalyst can be well regenerated after high temperature treatment, ensuring good repeatability of soot oxidation performance.