Efficient CO catalytic oxidation by the combination of cobalt and excellent carrier Ta2O5

Small size cobalt nanoparticles are highly dispersed on different crystalline forms of Ta 2 O 5 (amorphous, T, M, H) by impregnation method, which is then introduced to catalytic oxidation of CO. The experimental results show that Co 3 O 4 /M-Ta 2 O 5 exhibits the highest CO conversion efficiency compared with Co 3 O 4 loaded on amorphous-, T-, and H-Ta 2 O 5 , and the pure Co 3 O 4 and M-Ta 2 O 5 . The temperature of 90 % CO conversion rate is approximately 170 °C at the high space velocity of 780,000 h −1 . Besides, the effect of oxygen concentration, space velocity, CO concentration, as well as different ratio of Co: Ta on CO conversion have been studied. Moreover, XRD , SEM, TGA , BET and H 2 -TPR characterizations reveal that Co 3 O 4 is uniformly distributed and does not change the structure crystalline of Ta 2 O 5 , and there is strong interaction between cobalt active component and Ta 2 O 5 support, which might be beneficial for CO conversion. Furthermore, the reaction mechanism has been investigated by X-ray photon spectroscopy and in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs), which suggest that Co 3+ is the active component and lattice oxygen as well as adsorbed oxygen play a critical role in CO oxidation.