This study explored the superior citrate method (CM) to synthesize Mn–Ce bi-oxides on 3D monolithic Ni-foam (NF) catalysts for the selective catalytic reduction of NO by NH₃ (NH₃-SCR). The 17 wt% Mn(7)Ce(3)O_x/NF (CM-17) catalyst shows the NO_x conversion of 98.7% at 175 °C and 90% in the presence of 10 vol% H₂O. It is revealed that the combination of surface-active oxygen (formed by high-level oxygen vacancies) and strongly oxidized Mn⁴⁺ species promots the Fast-SCR reactions, in which Mn⁴⁺ species play a leading role in NH₃-SCR reaction, and the unsaturated Ni atoms and also Ce³⁺ species promote electron exchange and thus improve the redox performance. The coexistence mechanisms of Fast-SCR reactions and E-R pathways are observed over Mn-CeO_x/NF catalyst, which may be promoted by the Brønsted sites at low temperature. In addition, the heat resistance, stability, 3D monolithic porous structure and excellent physical properties of foam nickel provide a unique growth substrates for catalysts preparation and reaction sites for NO_x purification. Therefore, industrial application of Mn–Ce bi-oxides loaded on 3D monolithic is proposed to be achieved through reasonable preparation methods.

本研究探索了在 3D 整体式泡沫镍 (NF) 催化剂上合成 Mn-Ce 二氧化物的优越柠檬酸盐法 (CM)，用于 NH ₃ (NH ₃ -SCR) 选择性催化还原 NO。17 wt% Mn(7)Ce(3)O _x /NF (CM-17) 催化剂在 175 °C 下的 NO _x转化率为 98.7%，在 10 vol% H ₂ O存在下为 90%。揭示了表面活性氧（由高水平氧空位形成）和强氧化的Mn ⁴⁺物质的结合促进了Fast-SCR反应，其中Mn ^{4+物质在NH} ₃ -SCR反应中起主导作用，并且不饱和Ni原子和Ce ³⁺物种促进电子交换，从而提高氧化还原性能。在 Mn-CeO _x /NF 催化剂上观察到 Fast-SCR 反应和 ER 途径的共存机制，这可能由低温下的 Brønsted 位点促进。此外，泡沫镍的耐热性、稳定性、3D 整体多孔结构和优异的物理性能为催化剂制备和 NO _x净化的反应位点提供了独特的生长基质。因此，建议通过合理的制备方法实现负载在 3D 单片上的 Mn-Ce 二氧化物的工业应用。