Promotional effects of Pt-CeO2 fabricated by hydrothermal leaching of Al78Ce22-xPtx (x=0, 0.1) intermetallic compound for efficient catalytic CO oxidation

Hydrothermal leaching is one of the leaching processes to remove Aluminum (Al) in Al-based intermetallic compounds (ICS) to obtain a better catalytic performance. Herein, a facile method is introduced for hydrothermal leaching of Al78Ce22-xPtx (at%; x = 0, 0.1) ICS to obtain CeO2 and Pt-CeO2 catalysts for CO conversion. Successively, 95% and 94% of Al were leached out after hydrothermal leaching of Al78Ce22 and Al78Ce21.9Pt0.1 ingots. The hydrothermal leaching of ingots led to irregular structure transformed into a rod-like structure after hydrothermal leaching of ingots. The existence of metallic Pt and the effect of hydrothermal leaching resulted in better catalytic CO conversion for Al78Ce21.9Pt0.1 after hydrothermal leaching. The interaction between Pt-O-Ce and active sites led to good catalytic performance for Al78Ce21.9Pt0.1 after hydrothermal leaching. It was hypothesized that the reaction followed the Mars-van Krevelen (M-vK) mechanism. Further, Al78Ce21.9Pt0.1 after hydrothermal leaching possessed higher activation energy (43 kJ/mol) than other samples, which caused excellent catalytic performance. Besides, good thermal stability after catalysis for all the samples was affirmed by XRD analysis.

Automated summary

In this study, a facile hydrothermal leaching method was introduced to remove aluminum from Al-based intermetallic compounds (ICS) and obtain CeO2 and Pt-CeO2 catalysts for CO conversion. The hydrothermal leaching process resulted in high leaching efficiency and transformation of the structure of the ICS. Additionally, the presence of metallic Pt and the effect of hydrothermal leaching improved the catalytic performance for CO conversion. The interaction between Pt-O-Ce and active sites contributed to the enhanced catalytic activity. The reaction was hypothesized to follow the Mars-van Krevelen (M-vK) mechanism, and the hydrothermally leached sample exhibited excellent catalytic performance with higher activation energy.