Alloying of Ni-Si intermetallic compounds and Co/Fe/Mn with enhanced CO oxidation activity

The novel Ni-Si intermetallic compounds are fabricated by elemental powder metallurgy. This study explores the synthesis of a series of catalysts (Ni-Si-M, M=Co, Fe, Mn) by alloying to augment the low-temperature efficiency of CO oxidation using Ni-Si intermetallic compounds. It is found the low-temperature catalytic activity of Ni-Si-Co, Ni-Si-Fe, and Ni-Si-Mn catalysts are significantly enhanced compared to the original Ni-Si. The catalytic activity among the catalysts ranks as follows: Ni-Si-Co > Ni-Si-Fe > Ni-Si-Mn > Ni-Si. The apparent activation energy (Ea) for Ni-Si-Co was the lowest at 57.3 kJ/mol, suggesting its efficient catalytic oxidation of CO. Additionally, the addition of Co, Fe and Mn elements actually promotes the generation of Ni 2+ as the CO adsorption site in the original Ni-Si. The addition of Co element also leads to the formation of Co 2+ as the adsorption site of O 2 in the process of CO oxidation reaction. The synergistic adsorption of Ni 2+ and Co 2+ to CO and O 2 promotes the CO oxidation reaction. Additionally, the catalysts demonstrate robust long-term stability in atmospheres containing H 2 O and SO 2 , with CO conversion initially suppressed but subsequently recovering and stabilizing at over 90%. This investigation offers novel insights into enhancing the low-temperature activity and stability of catalysts.