NH3-Selective Catalytic Reduction of NOx to N2 over Ceria Supported WOx Based Catalysts: Influence of Tungsten Content

A series of HPW/CeO2 catalysts generated from 12-tungstophosphoric acid, H3PW12O40 (HPW), supported on ceria and presenting different tungsten loadings (2, 4.5, 9, 16, 40 wt% W) were prepared characterized by N2 physisorption, XRD, IR, Raman, UV-Vis. The characterization techniques suggested that low loading resulted in mainly isolated sites, while high produced polymeric or clusters. Those materials exhibited activity NH3-SCR NOx into N2. Moreover, the experiments indicated (2% HPW/CeO2) displayed highest with a remarkable selectivity (99%) at medium-high temperature (300–515 °C), owing to amount monomeric tungstate coverage catalyst surface.