Cu-Ce-O catalyst revisited for exceptional activity at low temperature CO oxidation reaction

Abstract

In the present study, CexCu1?xO2?? (x = 0, 0.3, 0.5, 0.8, 0.9, and 1) catalysts were synthesized using a facile and reproducible combustion method and were evaluated towards the CO oxidation (CO-OX) and CO preferential oxidation (CO-PROX) reactions as inexpensive and active catalytic materials. Pure ceria and copper oxide were compared to CexCu1?xO2?? mixed metal oxides for benchmarking purposes. The catalysts were prepared using citric acid (C6H8O7) as fuel and nitrate salts of cerium and copper as oxidizers under fuel rich conditions. A variety of techniques including XRD, EDX, BET, SEM, Raman, XPS, H2-TPR and CO2-TPD, were used to analyze the microstructural, thermal and redox properties that may influence CO oxidation performance. A profound effect of Cu content was revealed that not only impacts the structural and redox properties of the catalysts but also affects the catalytic activity. The Ce0.8Cu0.2O2?? catalyst presented the most promising performance among many similar (Cu-Ce-based catalysts) as well as noble supported catalysts published in the literature with T50 = 62 �C and T100 = 78 �C, an activity that coincides with the availability of labile oxygen species at low temperature (T < 100 �C) and the enhanced CO2 desorption at low temperature (low CO2-philicity) of this catalyst. � 2018 Elsevier B.V.