The introduction of Mn component improves the selectivity of NO adsorption separation in simulated flue gas of Co-MOF-74 at ambient conditions

Synthesized of bimetallic Mn0.17Co0.83-MOF-74 via the solvent-thermal method, which retained the same structure as that of monometallic MOF-74, and the two metals were uniformly dispersed in the crystals of Mn0.17Co0.83-MOF-74. The introduction of Mn gave the Mn0.17Co0.83-MOF-74 a higher pore number than the monometallic MOF-74, exposing more accessible metal active sites, and the in situ IR demonstrated that NO adsorption on Mn0.17Co0.83-MOF-74 was modelled as the linear adsorption of metal-centred Co (II)NO and Mn (II)NO, with strong interactions of adsorbed NO with both metal sites, suggesting that the introduction of Mn provided new accessible metal adsorption sites for NO that increased the adsorption of NO. The NO adsorption capacity of bimetallic Mn0.17Co0.83-MOF-74 was significantly increased to 160.3 cc.g(-1) at ambient conditions, and the adsorption selectivity of NO/CO2 achieved 397, which was 37% higher than monometallic Co-MOF-74, and 214% higher than Mn-MOF-74 at low pressure. Furthermore, when exposed to a simulated mixed atmosphere, the Mn0.17Co0.83-MOF-74 exhibited a NO/CO2 adsorption selectivity of 35.5 and demonstrated favourable recyclability. These findings indicated that the bimetallic Mn0.17Co0.83-MOF-74 outperforms traditional materials in the adsorption separation of flue gas NO, positioning it as a material of choice in this field.