Phosphorus were employed to investigate the influences on the acid sites and reaction mechanism of FeTiO_x SCR catalyst. The introduction of phosphorus inhibited the SCR activity by suppressing the redox property, decreasing the surface acidity and reducing the surface area. In particular, phosphorus preferentially bonded to the electron-deficient Ti⁴⁺ and Fe³⁺ cations on the surface as P-O-Fe and P-O-Ti, thereby blocking the Lewis acid sites (Fe-NH₃ or Ti-NH₃). Although phosphate provided additional Brønsted acid sites (P-O-NH₄⁺), the larger decrease of Lewis acid sites results in the decrease of total surface acidity. The newly formed Brønsted acid sites showed less SCR active at low temperature and exhibited high thermal stability and reactivity at high temperature, which leads to a new pathway following the L-H mechanism and an enhancement of high temperature performance.

用磷研究了FeTiO _x SCR催化剂对酸位和反应机理的影响。磷的引入通过抑制氧化还原特性，降低表面酸度和减小表面积来抑制SCR活性。特别地，磷优先以PO-Fe和PO-Ti的形式键合至表面上的电子不足的Ti ⁴⁺和Fe ³⁺阳离子，从而阻断路易斯酸位点（Fe-NH ₃或Ti-NH ₃）。尽管磷酸盐提供了额外的布朗斯台德酸位点（PO-NH ₄ ⁺），路易斯酸位点的较大减少导致总表面酸度的降低。新形成的布朗斯台德酸位点在低温下显示较少的SCR活性，在高温下显示出高的热稳定性和反应性，这导致遵循LH机理的新途径和高温性能的增强。