Mesoporous Co‐Al oxide nanosheets as highly efficient catalysts for CO oxidation

Abstract We report mesoporous Co‐Al oxide nanosheets (Co x Al‐Ns, where x denotes the Co/Al ratio in the samples) prepared by calcination of CoAl‐hydrotalcite and subsequent alkaline treatment. X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and X‐ray photoelectron spectroscopy measurements show that the prepared Co‐Al oxide nanosheets (Co x Al‐Ns) are very thin (10–15 nm) and exhibit high mesoporosity (3–5 nm). Catalytic CO oxidation tests reveal that the Co x Al‐Ns exhibit excellent catalytic performances at relatively low temperatures: for example, the Co 2.5 Al‐Ns catalyst could achieve 99% CO conversion at −98°C. Kinetic studies and experimental investigations indicate that the high activity of the Co 2.5 Al‐Ns sample is strongly related to the abundance of active sites associated with the large Brunauer–Emmett–Teller surface area. The Co 2.5 Al‐Ns catalyst also achieves full conversion of CO in tests performed with a gas mixture simulating automobile exhaust gas at 200°C. After loading the Co 2.5 Al‐Ns on a porous ceramic substrate, the obtained Co 2.5 Al‐Ns/PC shows high activity and stability in CO oxidation process. These features are potentially important for future industrial applications of these catalysts.