Performance of mesoporous CeO2-Cr2O3 mixed metal oxides applied to benzene catalytic combustion

In this paper, a hydrothermal method was used to prepare (Ce,Cr)-MOF with different Ce/Cr molar ratios and then a series of CeO2-Cr2O3 mixed metal oxides (CeCr-MMO) with mesoporous structure were prepared by thermal decomposition of these MOFs at different temperatures. After a series of charac-terization techniques were applied to test the physicochemical properties of the materials, it is found that thermal decomposition temperature (TDT) and Ce/Cr molar ratios have important effects on the structure and performance of CeCr-MMO. As the TDT reaches 400 degrees C and above, (Ce,Cr)-MOF can be completely decomposed to form CeCr-MMO. The catalyst with Ce/Cr molar ratio of 4:1 has the highest catalytic activity, which can completely degrade benzene at 230 degrees C. It is concluded that the interaction between CeO2 and Cr2O3 is helpful for increasing the concentration of Ce3+, Cr6+ and lattice oxygen species (OLatt) on the catalyst surface, thus improving the catalytic performance. Moreover, CeCr(4:1)-MMO-40 0 shows excellent durability against the presence of chlorobenzene and H2O during 100 h continuous reaction.(c) 2022 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.

Automated summary

In this study, (Ce,Cr)-MOF with different Ce/Cr molar ratios were prepared using a hydrothermal method, and a series of CeO2-Cr2O3 mixed metal oxides (CeCr-MMO) with mesoporous structure were obtained by thermal decomposition of these MOFs at different temperatures. The physicochemical properties of the materials were characterized, and it was found that thermal decomposition temperature (TDT) and Ce/Cr molar ratios significantly influenced the structure and performance of CeCr-MMO. The catalyst with a Ce/Cr molar ratio of 4:1 exhibited the highest catalytic activity, completely degrading benzene at 230 degrees C. The interaction between CeO2 and Cr2O3 was concluded to enhance the concentration of active species on the catalyst surface, thereby improving the catalytic performance. Moreover, CeCr(4:1)-MMO-400 showed excellent durability against chlorobenzene and H2O during continuous reaction for 100 hours.