Photothermal catalytic hydrolysis of COS with enhanced efficiency over constructed alkali-modified La-Ti catalyst: Adjusting photogenerated electron behavior through metal‐support interactions

Abstract

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 (TiO2, thermal treatment) to 8.43 × 10-4 s−1 (La-Ti@K, photothermal treatment), and the H2S selectivity exceeded 99%. This was because La doping increased the density of basic sites on TiO2, which promoted the continuous dissociation of H2O in the system and the regeneration of –OH under UV irradiation. Moreover, the photogenerated electrons from TiO2 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 TiO2 might be responsible for these phenomena. In addition, theoretical calculations revealed that light-induced electron transfer was conducive to H2O 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.