Efficient catalytic hydrolysis of HCN by La-TiO2: La modulates the generation of surface-rich hydroxyl environment

Hydrogen cyanide (HCN), a common toxic and hazardous air pollutant in industrial exhaust, catalytic hydrolysis of HCN has been the focus of air pollution control research. In this study, a catalyst material (La-TiO 2 ) with high catalytic hydrolysis activity for HCN was obtained by loading La 2 O 3 on the TiO 2 surface, which could realize the complete conversion of HCN at 150 °C with high selectivity of NH 3 and CO 2 . The relevant characterization confirms that La 2 O 3 can be uniformly distributed on the TiO 2 , which can adjust the acid-base structure of the catalyst surface and induce the generation of multi-hydroxyl structures in TiO 2 . On this basis, the combination of in-situ technique and density functional theory (DFT) calculations confirmed that the loading of La 2 O 3 prompted the La-TiO 2 catalyst to activate H 2 O to generate surface hydroxyl groups (-OH), which further enriched the hydroxyl groups on TiO 2 and substantially improved the hydrolysis activity and NH 3 selectivity of the catalyst. And the study confirms that the hydroxyl-rich environment easy combine with the reaction intermediate (formic acid) to generate CO 2 and H 2 O, which accelerated the reaction rate, thus improving the conversion efficiency of HCN and lowering the catalytic conversion temperature. In addition, O 2 can continuously consume the remaining hydrogen atoms after the dissociation of H 2 O to generate hydroxyl groups again, thus effective enhancing catalyst stability. This study provides new theoretical support for the catalytic hydrolysis of HCN and new insights and ideas for the design and development of catalysts for the catalytic hydrolysis of HCN.