Influence of synergy effect over the catalyst derived from CuFe-LDHs on SCR-C3H6: An in situ DRIFTS study

Abstract

The synergy between multi-metals can enhance the catalytic performance of catalysts but lacks research from the perspective of reaction mechanisms. Hence, the correlation between the synergy effect and the SCR-C₃H₆ reaction mechanism was investigated over the CuFe-LDOs catalyst derived from the precursor CuFe-LDHs, and single metal oxide catalysts (CuO, Fe₂O₃). XPS and H₂-TPR techniques reveal the existence of the synergy effect between Cu and Fe, which results in the superior catalytic activity of the CuFe-LDOs catalyst than single metal oxide catalysts, as well as the generation of CuFe₂O₄ over the CuFe-LDOs catalyst. Numerous static and dynamic In situ DRIFTS and TPSR experiments indicate that the synergy effect encourages the creation of nitrogenous species, especially active intermediates like monodentate, bidentate, and bridging nitrates. Besides, the production of active carboxylate acetate also obtains enhancement owing to the synergy effect. Importantly, R-NCO generates and accumulates profited from the synergy effect, working as the vital intermediate for SCR-C₃H₆, and is ultimately hydrolyzed to CO₂, N₂, and H₂O. These results demonstrate that the improvement of catalytic activity for the CuFe-LDOs catalyst benefits from the promotion of the synergy effect on active intermediates. Eventually, a possible SCR-C₃H₆ reaction pathway on the CuFe-LDOs catalyst is established.