Insights into the Synergistic Promotion Effect of Cu and W Modification on the Catalytic Performance of α-Fe2O3 for NH3-SCR of NOx

A dual-element modification strategy was proposed to promote the catalytic performance of the α-Fe2O3 catalyst for the selective catalytic reduction of NOx by NH3 (NH3-SCR of NOx) at both low and high temperatures. By optimizing the loading amount of CuO (4 wt %) and WO3 (5 wt %), a wide operating temperature window (150-350 °C) was achieved on the modified α-Fe2O3 catalyst (W5/Cu4/Fe). Further characterizations revealed that the enhanced low-temperature activity could be attributed to the improved redox performance of α-Fe2O3 through CuO modification, while the superior high-temperature activity was primarily ascribed to the enhanced surface acidity induced by WO3 modification. The synergistic effect of CuO and WO3 modifications facilitated the NH3-SCR reaction on the modified α-Fe2O3 catalysts to efficiently proceed through the Eley-Rideal (E-R) mechanism pathway. This provided compelling evidence that the catalytic performance of NH3-SCR catalysts at different temperatures was dominantly governed by distinct factors (e.g., redox property and surface acidity), offering valuable insights for the rational design of robust catalysts for NOx abatement.