Combined XPS and TPR study of sulfur removal from a Pt/BaO/Al2O3 NO x  storage reduction catalyst

Abstract

catalysts (1 wt% Pt, 10 wt%BaO) were sulfated under conditions simulating a real NSR catalyst operation. Comparative TPR and XPS studies of sulfur removal from Pt/Al 2 O 3 and Pt/BaO/Al 2 O 3 catalysts indicate that the sulfur removal from Al 2 O 3 surface precedes reductive decomposition of BaSO 4 (250-400°C). Barium sulfate decomposition started with further increase in desulfation temperature at the point of surface atomic ratio Ba:S = 1 ($450 o ). Simultaneously, an intensive formation of sulfide species on the catalyst surface was observed. Thermodynamic analysis of the desulfation process allows us to hypothesize that barium sulfide formation may hinder sulfur removal under reducing conditions.

The simple, template free synthesis of a Bi2S3–ZnO heterostructure and its superior photocatalytic activity under UV-A light

“…3e). 30 The optoelectronic properties of the heterostructured Bi 2 S 3 -ZnO were explored using UV-vis diffuse reflectance Photoluminescence (PL) is useful to understand the fate of the electron-hole pairs in semiconductor particles. 31 Fig.…”

Fine-Tuning the Dispersion and the Mobility of BaO Domains on NOx Storage Materials via TiO2 Anchoring Sites

“…[9][10][11][12] Thus, efforts toward improving the catalytic tolerance against sulfur poisoning and designing highly active and stable novel NSR catalysts are extremely crucial. [13][14][15] One of the areas that have been a major target in numerous studies [16][17][18][19] in the past decade is the development of an optimal support material that will improve the catalytic stability by assisting the formation of sulfur resistant species in the catalytic system.…”

“…The main drawback of the typical NSR catalysts is the high affinity of these catalysts toward sulfate formation (originating from the presence of sulfur containing compounds in the exhaust feed), which leads to significant catalytic deactivation. − Thus, efforts toward improving the catalytic tolerance against sulfur poisoning and designing highly active and stable novel NSR catalysts are extremely crucial. − …”

Fe Promoted NOx Storage Materials: Structural Properties and NOx Uptake

“…Numerous studies − were directed toward the design of NSR catalysts with long-term durability, high activity, and improved sulfur tolerance by incorporation of additional oxides such as TiO 2 or Fe 2 O 3 to the catalytic Pt/BaO/γ-Al 2 O 3 system. For instance, in one of our recent reports, the nature of the Ti−Ba interactions on the Ba/Ti/Al NO x storage systems has been thoroughly investigated where it was found that the presence of TiO 2 has a considerable effect on the surface distribution of the NO x storage domains and the thermal stability of the stored nitrates on the surface.…”