Recent developments of core-shell structured catalysts for the selective catalytic reduction of NO_x with ammonia

Selective catalytic reduction of NO_x with ammonia (NH₃-SCR) is an efficient and established technology for removing NO_x emission from anthropogenic sources. The commercial de-NO_x catalysts based on V₂O₅-WO₃/TiO₂ possess some significant drawbacks limiting their applicability, including narrow operating temperature window, biotoxicity, poor hydrothermal stability and SO₂/H₂O intolerance. To circumvent these shortcomings, modifications of existing V₂O₅-WO₃/TiO₂ catalysts as well as development of novel catalysts have been investigated intensively. Recently, the unique properties of core-shell structures and their extensive application within, e.g. biotechnology, pharmaceutics, electrochemical cells, optics as well as catalysis have also made their use in NH₃-SCR attractive. This review summarizes recent material developments and provides an up-to-date appraisal of core-shell structured catalyst design and assembly for NH₃-SCR, including classification, synthesis, catalytic performance as well as structure-property relationships. The review may inspire future developments within the NH₃-SCR technology leading to novel catalyst designs with improved de-NO_x performance.