Soft- and reactive landing of mass-selected, hyperthermal (< 100 eV), polyatomic ions onto surfaces constitutes a novel approach for the highly controlled preparation of catalysts. Mass selection enables species with well defined charge and chemical composition to be delivered to surfaces under controlled conditions, thereby avoiding purification steps which are critical with conventional catalyst synthesis techniques. Mass spectrometry also provides a unique opportunity for the preparation of materials that are either inaccessible or extremely difficult to prepare in solution. A new instrument has been designed and constructed at PNNL that enables in situ reactivity and time of flight secondary ion mass spectrometry analysis of surfaces prepared or modified through soft- and reactive landing. The capabilities of this apparatus for the preparation and analysis of catalyst materials are demonstrated for two systems consisting of monolayer catalysts produced by the deposition of organometallic metal-salen and ruthenium bipyridine cations onto self assembled monolayer surfaces. It shown that through soft landing of vanadium-salen cations and a proton donor it is possible to achieve proton mediated reactivity in an inert fluorinated monolayer that is normally only observed in highly acidic solutions. In addition, it is demonstrated that gas-phase ligand stripping may be used to generate highly reactive undercoordinated metal complexes which exhibit enhanced activity towards reactive landing in comparison to fully ligated species. The immobilized complexes, which are covalently bound to the surface, are shown to exhibit catalytic activity when exposed so gaseous reagents.        

Grant Edward Johnson*, Pacific Northwest National Laboratory, United States
Wen-Ping Peng, National Dong Hwa University, Taiwan
R Graham Cooks, Purdue University, United States
Julia Laskin, Pacific Northwest National Laboratory, United States

*presenting author