Ammonia is an important source of malodor that is becoming more prevalent in urban cities. Indeed, malodor is a rampant environmental pollution problem that is prominent in places that transport, process and store organic and biological wastes such as drainage and sewers, waste and recycling stations, wastewater and solid waste treatment facilities, incineration plants and landfills. Breathing discomfort, eye and throat irritations and headaches are common complaints related to malodor. Long-term exposure is known to cause olfactory dysfunction, sleep and eating disorders and even behavioral problems in people. Vanadium oxides are known to catalyze many partial oxidation reactions including the partial oxidations of alkanes, olefins and alcohols and more recently, the selective oxidation of NH3 to N2. The versatility of the vanadium oxide catalyst is attributed to the facile transition among the various active vanadium oxide species and the formation of oxygen vacancies that facilitates the transport and storage of reactive oxygen. This work reports a new environmental catalyst based on doped VOx/TiO2 catalyst that has excellent activity and selectivity for selective oxidation of NH3 to N2 at room temperature. NOx formation was not detected and the catalyst can tolerate high humidity. The structure, composition and chemistry of the catalyst were analyzed by in situ and operando techniques to reveal that vanadium oxides were present mainly as monomeric and polymeric species on these catalysts even as the V-loading approach theoretical monolayer coverage. Operando spectroscopic method is instrumental in revealing how the vanadium species evolve during the reaction and how they relate to the reaction behavior.

Selective ammonia oxidation on vanadia-titania catalysts

248th National Meeting (2014)

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