Influence of WOx on the performance of a CrOx–WOx catalyst for the selective catalytic reduction of NOx with NH3

•>90 % NOx conversion is obtained in 230–390 °C with the W/Cr molar ratio fixed at 0.8.•The operation temperature window of CrOx shifts to higher temperatures via adding WOx.•Adding WO3 enhances the acidity of the catalyst at the cost of its oxidative ability.•E-R mechanism dominates in the SCR reactions over the CrOx and CrOx-WOx catalysts.