Regulating the morphology of Cu/CeO2 catalysts to enhance their water-resistant for low temperature CO oxidation
Herein,tube-,rod-and particle-like Cu/CeO2 catalysts were synthesized and their structure-performance relationship for CO oxidation in moist conditions was explored.The results revealed that the tube-like catalysts(CuCe-NT)exhibited excellent low-temperature activity and superior H2O resistance stability.The characterization results indicated that CuCe-NT catalyst had a lower crystallinity,larger surface area and more structural defects in comparation with rod-like(CuCe-NR)and particle-like(CuCe-NP)samples,which greatly strengthened the interactions between CuOx and CeO2,thus boosting the redox of Ce4+/Ce3+and Cu2+/Cu+,and the surface enrichment of Ce3+and Cu+,further facilitating the CO adsorption and oxidation.Moreover,the hollow structure of CuCe-NT catalyst with a large pore size effectively inhibited the associatively adsorption of H2O,suppressing the generation of inert OH groups on oxygen vacancies,and thus maintaining its higher oxidization in the presence of water.In situ-DRIFTS showed that compared to CuCe-NP catalyst,the nanotube structure of CuCe-NT catalyst alleviated the competitive adsorption of H2O with CO,and inhibited the formation of bridged carbonates,thus ensuring the CO oxidation under humid atmosphere.This study revealed the effect of catalyst structure on its resistance of H2O in terms of H2O adsorption type and reaction mechanism,thus providing an ingenious strategy for the design of H2O-resistant CO oxidation catalysts.
water resistanceCO oxidationCu/CeO2 catalyststailorable morphologystructural defects
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