Study On Co₃O₄-CeO₂/MCM-41 And Co₃O₄/mesoporous CeO₂ For Preferential Oxidation Of CO In H₂ Gas

Mesoporous materials can be potentially applied in many fields due to the characteristics of high specific surface area, ordered pore arrangements, the uniformity of pore size and high dispersion of loaded metal. Especially mesoporous materials have been probably applied in catalysis as support. Preferential oxidation of carbon monoxide is an optimal method for the purification of hydrogen-rich gas used for fuel cells. In this process, developing efficient catalysts is of great significance.So in our work, the main purpose is to explore a new approach to prepare catalyst for CO preferential oxidation.In this paper, MCM-41 support and mesoporous CeO₂ support were used as support in Co₃O₄-CeO₂/MCM-41 and Co₃O₄/mesoporous CeO₂ catalysts. We applied these catalysts in PROX. The results show that Co₃O₄ supported mesoporous CeO₂ catalysts exhibit much higher activity than Co₃O₄-CeO₂/MCM-41 catalysts. So we further study Co₃O₄ supported mesoporous on CeO₂ catalysts. The influence of preparation method, the content of active component and calcination temperature on catalytic performance was investigated. We also tested the effect of the addition of CO₂ and H2O in the feed gas and the space velocity for PROX over Co₃O₄/mesoporous CeO₂ catalyst. The catalysts are characterized by XRD, N2-BET adsorption and DTA-TG.The main results are as follows:1. The long-range orderded mesoporous MCM-41 have been synthesized using the template of CTABr. The average pore size of mesoporous CeO₂ is 4.8nm.2. The complete conversion of CO has been observed over the Co₃O₄/mesoporous CeO₂ catalyst. Furthermore, CO can be totally removed in comparatively wide temperature range. In sum, Co₃O₄/mesoporous CeO₂ show better catalytic performance than Co₃O₄-CeO₂/MCM-41 catalysts.3. The excellent catalytic performance of Co₃O₄/mesoporous CeO₂ is due to high specific surface area of mesoporous CeO₂, which enhance the dispersion and stability of loaded Co₃O₄.4. The catalytic tests and characterization results show that the higher surface area, the higher dispersion. The high dispersion of active component results in high catalyst activity. On the other hand, the interaction between active component and support is beneficial for catalyst activity.