The LNT (lean NOx trap) is generally considered as one of the promising solutions for the exhaust control of gasoline lean burn and diesel engine to meet future requirements on emission levels. In the LNT technology, an active (alkali and/or alkaline earth) oxide material takes up NOx under lean engine operation conditions and stores them as nitrates. The desulfation steps on sulfated Pt-BaO/Al2O3 NOx storage materials were studied using in situ synchrotron-based techniques. These in situ techniques allowed to understand the changes in the morphology and oxidation states of sulfur species during desulfation processes. This is an abstract of a paper presented at the 2007 AIChE Annual Meeting (Salt Lake City, UT 11/4-9/2007).