Photothermal catalytic hydrolysis of COS with enhanced efficiency over constructed alkali-modified La-Ti catalyst: Adjusting photogenerated electron behavior through metal‐support interactions
The low-temperature conversion of corrosive carbonyl sulfide (COS) in steel by-product gas is essential for the clean utilization of this gas. Herein, La-Ti@K catalysts doped with La nanoparticles were shown to exhibit significant photopromoted thermocatalytic activity and stability under UV light irradiation. At a reaction temperature of 60 °C, the TOF value increased from 4.84 × 10 -4 s −1 (TiO 2 , thermal treatment) to 8.43 × 10 -4 s −1 (La-Ti@K, photothermal treatment), and the H 2 S selectivity exceeded 99%. This was because La doping increased the density of basic sites on TiO 2 , which promoted the continuous dissociation of H 2 O in the system and the regeneration of –OH under UV irradiation. Moreover, the photogenerated electrons from TiO 2 were transferred to La to maintain the metallic La nanoparticles, as well as to ensure the activation and photothermal hydrolysis of COS. The presence of a suitable electron-metal-support interaction (EMSI) between the electron-rich La nanoparticles and TiO 2 might be responsible for these phenomena. In addition, theoretical calculations revealed that light-induced electron transfer was conducive to H 2 O dissociation and COS activation, while La doping reduced the free energy of the hydrolysis reaction. This work demonstrates the effectiveness of La-Ti@K catalyst in COS photothermal hydrolysis and provides a theoretical basis for further understanding of the photothermal catalytic mechanism.
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