Confinement of MnO@FeO core-shell catalyst with titania nanotubes: Enhanced N selectivity and SO tolerance in NH- SCR process.

Surface interface regulation is an important research content in the field of heterogeneous catalysis. To improve the interface interaction between the active component and matrix, tremendous efforts have been dedicated to tailoring the morphology, size, and structure of composite catalysts. In this work, we report a confinement strategy to synthesize a series of core-shell catalysts loaded with metal oxides on titania nanotubes (TNTs), which were applied to the selective catalytic reduction of NO with ammonia. Interestingly, the core-shell catalyst with confinement of TNTs exhibited the remarkable activity at low temperature region, N selectivity and sulfur tolerance. Benefiting from the superior interfacial confinement characteristic of TNTs and FeO, strong component interactions, the surface acid sites and strong oxidizability of MnO were properly regulated, thus obtained the outstanding activity, N selectivity and provide chemical protection to effectively prevent SO poisoning. As far as the reaction mechanism, we found that the adsorption and reactivity of Lewis acid sites were the dominant factors affecting the activity in the NH-SCR process by in situ DRIFT spectra. In general, our work provides an innovative strategy for constructing an TNTs-enwrapped nanocomposite with nano-confinement and core-shell structure to improve the low temperature SCR process.