NO direct decomposition: progress, challenges and opportunities

NO direct decomposition is deemed as the ideal technology to diminish NO from exhaust waste owing to its cost-effectiveness and eco-friendliness. However, its wide application is seriously impeded by the low activity and stability of catalysts under real conditions. Here, the advances in catalysts for NO direct decomposition have been reviewed including noble metals, simple metal oxides, rare-earth oxides, complex metal oxides and zeolites, focusing on their distinctive properties and trying to provide thoughts on catalyst development over more than one century. The present knowledge of the active sites and various catalytic mechanisms for NO direct decomposition is also introduced. Afterwards, the challenges facing the catalysts with respect to susceptibility in various co-fed gases are discussed in detail. Finally, candid suggestions on the opportunities to achieve the practical application of NO direct decomposition technology are put forward. It is expected that more efforts will be put into it and thus accelerate the development and application of this ideal NO removal technology.