ABATEMENT OF HARMFUL CARBON MONOXIDE OVER THE NICKLE DOPED CO3 O4 CATALYST

Abstract

This work aimed at evaluating the effect of nickle (Ni) dopant on the catalytic performance of Co3 O4 catalyst for abatement of harmful carbon monoxide (CO), a resistance toward sintering and durability of catalytic activity were also pursued. Choose the Co(NO3 )2 ×6H2 O(aq) as precursor and NaOH as precipitant to prepare cobalt oxide (Co3 O4 ) with precipitation method, then calcined at 300 and 500 °C, separately (named as C3 and C5). The Ni dopant (0.1 ~ 5 wt%) was added by deposited precipitation through Ni(NO3)2 ×6H2 O(aq) with drop wisely added NaOH(aq) into suspended Co3 O4 solution, then put the NaOCl for oxidation to obtain series 0.1%Ni-Co3 O4 , 0.2%Ni-Co3 O4 , 1%Ni-Co3 O4 and 5%Ni-Co3 O4 catalysts. All catalysts were characterized through BET, XRD, TEM/SEM, Raman, ICP and TPR instruments, and evaluated the catalytic performance of CO oxidation with a self-devised fluidized micro-reactor. It was observed that the calcination temperature and loading of dopant remarkably influenced the physicochemical characteristics and catalytic performance of the catalysts. Preferential catalyst was obtained for calcination at 300 °C and loading of Ni dopant below 1%. The doping of Ni on the surface of Co3 O4 enhanced the performance due to the inducing of synergistic effect between Co3 O4 and NiO, while the excessive NiO incorporated to the surface constrained the activity due to the abundant NiO on the surface, overlaying the active sites caused the decreasing of surface area and reducible capacity. Among these series Ni-Co3 O4 catalysts, the 0.2%Ni-Co3 O4 (C3) catalyst behaved an eminent activity with T50 of 98 °C and durability without apparent deactivation for 50 hr reaction at 125 °C. The excellent performance is primarily attributed to the synergistic effect and formation of NiCo2 O4 composite oxide.