Mechanisms for Catalytically Abating Organosulfur Compounds with H2O2 Formed In Situ
Abstract
The objective of this proposal is to develop a fundamental understanding of the reaction pathways and driving forces that form H2O2, create M+-OOH* at Lewis acid sites, and selectively oxidize organosulfur compounds. The research will focus on two aims. First, we will identify active surface intermediates and mechanisms for low temperature oxidations on high surface area metal oxides. Second, we will investigate bifunctional systems for producing and utilizing in situ H2O2 to oxidize organosulfur compounds. A combination of kinetic and spectroscopic (in situ infrared spectroscopy and UV-vis) measurements will be used to probe the elementary steps and reactive intermediates involved in the oxidation of unsaturated C=C bonds in organic molecules and S-functions in organosulfur compounds. This chemistry will be studied on a series of metal oxide catalysts which contain isolated active metal atoms (e.g., Ti, Ta, and Nb) within zeolite frameworks or on mesoporous silica surfaces. In situ infrared and UV-Vis spectroscopy will be used to characterize active surface intermediates at the liquid-solid interface. We will develop modulation excitation spectroscopy and phase-sensitive detection will be used to measure the time-dependent coverages of reactive species on the surface of the metal cluster H2O2 formation catalysts and the metal oxide oxidation catalysts. Direct measurement of rates of competing surface reactions will be determined by transient kinetic experiments. We will develop a mechanistic understanding of multi-step oxidation processes that occur in bifunctional systems using a single reactant (dimethydibenzylthiophene, a model fuel contaminant). The metal oxide oxidation catalysts will be combined with metal cluster catalysts that efficiently convert H2 and O2 into H2O2 within the reactor. A combination of the rate measurements and in situ infrared and UV-Vis spectroscopy will be used to reveal complex reaction networks that occur on such combinations of oxide and metal cluster catalysts. This powerful approach will reveal critical information that can be used to optimize the design of these systems to help produce clean burning fuels.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 12, 2017
- Source ID
- W911NF1610128
Entities
People
- David W Flaherty
Organizations
- Army Contracting Command
- United States Army
- University of Illinois Urbana–Champaign