Nitrogen oxide (NOx) which is an important secondary aerosol precursor and involved in the formation of photochemical smog,has proved as an important family of air polluting chemical compounds.NO and NO2 with lone electron pair are endowed NOx with acidic character and active redox properties.Photocatalytic oxidation of NOx is very promising for the sustainable development,but the efficiency of the state-of-the-art semiconductor photocatalytic oxidation of NOx is far from satisfactory.