Construction of La/Al2O3 nanorod-like catalyst with rich basic sites: Enabling efficient conversion of COS-superior selectivity and theoretical insights
The introduction of surface basic sites to COS hydrolysis catalysts can improve H 2 O activation and COS adsorption, leading to enhanced catalytic performance. However, maximizing the concentration of basic sites remains a challenge due to the limited exposed surface area of these catalysts. Herein, a La/Al 2 O 3 catalyst with abundant alkaline sites to catalyze the hydrolysis of COS was prepared by a simple ammonia-assisted hydrothermal method. This synthesized La/Al 2 O 3 catalyst exhibits a thin rod-like structure formed by the random accumulation of nanoparticles. Lanthanum, one of the most abundant rare earth metals, is an ideal doping aid to further promote the COS-catalyzed hydrolysis performance of Al 2 O 3 . Characterization studies show that the proper lanthanum loading effectively enhances the formation of basic sites, leading to improved lattice oxygen reactivity and –OH adsorption capacity. As a result, the prepared La-loaded Al 2 O 3 nanorod sample with abundant basic sites exhibits nearly 100 % COS conversion and total H 2 S yield at 160 °C. In addition, the reaction pathways and deactivation mechanisms for selective catalytic hydrolysis of COS on the La-doped Al 2 O 3 catalyst were revealed by using in situ DRIFTS to evaluate COS adsorption and hydrolysis. Density functional theory calculations showed that La loading enhances the electron transfer between the La and Al atoms, improves the formation of basic sites, and enhances the adsorption of –OH. This study provides new insights into the design of efficient alumina-based catalysts for the catalytic hydrolysis of COS.
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