Trimetallic FeNiCu Atomic Clusters Supported on Carbon Matrix: Highly Active Catalysts for C₃H₆–SCR of NO

C 3 H 6 –SCR denitrification technology faces catalyst deactivation problems and low catalytic performance at medium-low temperatures. This study utilized the intermetallic synergies to prepare atomic cluster catalysts (FeNiCu/NC) by anchoring Fe–Ni–Cu on a carbon matrix to enhance the C 3 H 6 –SCR performance at medium-low temperatures. The synergistic effect of the Fe–Ni–Cu is reflected in the differences in the physicochemical properties of the catalysts, which is proved by several characterization techniques. Results showed that the FeNiCu/NC catalyst had a larger surface area (541.4 m 2 /g) and there were no metal oxides on the surface of the catalyst but abundant defective sites that anchored Fe/Ni/Cu atoms through N atoms to form M–N x active sites and atomic clusters. The hollow carbon morphology provides sufficient active sites for C 3 H 6 –SCR. The coordination environments of active sites were M–N x –C, Fe 2 /FeCu 2 /FeNi 2, Ni 3 /NiFe/NiCu 2, and Cu 4 /CuFe 2 /CuNi 2, where the synergistic action of trimetal leads to the presence of Fe–Ni–Cu–N x –C. The synergistic action of the Fe–Ni–Cu significantly improved the C 3 H 6 –SCR performance at medium-low temperatures. The FeNiCu/NC exhibited an 81% NO conversion at 150 °C under 2% O 2, 15% and 20% higher than FeNi/NC and FeCu/NC catalysts, respectively. Even at 4% O 2, the FeNiCu/NC catalyst was active to remove 78% NO and achieve a 93% N 2 selectivity at 150 °C and maintained a 100% NO conversion at 300–425 °C. The DRIFTS results demonstrated that NO and C 3 H 6 could combine with active O at metal cluster, M–N x, or defective oxygen sites to produce various intermediate species, wherein acetates and nitrates were the main active intermediates. Based on the DRIFTS results, a reaction pathway for C 3 H 6 –SCR over the FeNiCu/NC catalyst was proposed.