*Article* **Low-Temperature Selective NO Reduction by CO over Copper-Manganese Oxide Spinels**

**Fenglan Fan <sup>1</sup> , Lingjuan Wang <sup>1</sup> , Lei Wang <sup>1</sup> , Jinyu Liu 1,\* and Minghui Wang 2,\***


**Abstract:** Selective catalytic reduction of NO with CO (CO-SCR) has been suggested as an attractive and promising technology for removing NO and CO simultaneously from flue gas. Manganesecopper spinels are a promising CO−SCR material because of the high stability and redox properties of the spinel structure. Here, we synthesized CuxMn3−xO<sup>4</sup> spinel by a citrate-based modified pechini method combining CuO and MnOx, controlling the molar Cu/Mn concentrations. All the samples were characterized by SEM, EDX, XRD, TEM, H2−TPR, XPS and nitrogen adsorption measurements. The Cu1.5Mn1.5O<sup>4</sup> catalyst exhibits 100% NO conversion and 53.3% CO conversion at 200 ◦C. The CuxMn3−xO<sup>4</sup> catalyst with Cu-O-Mn structure has a high content of high valence Mn, and the high mass transfer characteristics of the foam-like structure together promoted the reaction performance. The CO-SCR catalytic performance of Cu was related to the spinel structure with the high ratio of Mn4+/Mn, the synergistic effect between the two kinds of metal oxides and the multistage porous structure.

**Keywords:** low-temperature; CO-SCR; Cu-Mn oxide spinels

**Citation:** Fan, F.; Wang, L.; Wang, L.; Liu, J.; Wang, M. Low-Temperature Selective NO Reduction by CO over Copper-Manganese Oxide Spinels. *Catalysts* **2022**, *12*, 591. https:// doi.org/10.3390/catal12060591

Academic Editor: Sónia Carabineiro

Received: 22 April 2022 Accepted: 27 May 2022 Published: 29 May 2022

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