In Situ Studies of the Decomposition of Simulated Chemical Warfare Agents on Nanoparticle Catalysts

摘要

Over the course of this grant, three main projects were conducted in to gain a better understanding of the decomposition of sulfur and phosphorus- based chemical warfare agents. The first project involved studies of the thermally-activated decomposition of dimethyl methylphosphonate (DMMP) on bimetallic Au-Pt clusters; one of the main problems with transition metal catalysts is that phosphorus is difficult to remove from the surface and poisons that catalyst for further reaction. Thus, the primary objective of this work was to understand whether the addition of a relatively unreactive metal like Au to a metal like Pt, which is active for DMMP decomposition, could enhance the ability to remove phosphorus from the surface. For the second project, the decomposition of methanethiol on Ni clusters as model systems for understanding destruction of sulfur-containing molecules as simulants for mustard gas. The third project deals with studies of DMMP decomposition on crystalline ceria thin films with various levels of reduction. The reaction mechanism for DMMP chemistry on ceria has been studied in detail. Although ceria retains activity for DMMP decompositon after multiple adsorption-reaction cycles, the surface is still poisoned by POx.