Effect of pH value on the microstructure and deNOx, catalytic performance of titanate nanotubes loaded CeO2

The relationship between catalytic performance and pH value of post-treatment of the catalyst supports-titanate materials was investigated and discussed. Three types of titanate nanotubes (TNTs) that are acidic TNTs (TNTs-1.6, pH value at 1.6), neutral TNTs (TNTs-7), and alkaline TNTs (TNTs-12) were synthesized by hydrothermal method with the controlled washing pH value and then were used as the catalyst supports for ceria. These titanate-supported ceria catalysts showed extremely different performance for the selective catalytic reduction in NO. The pH value had a notable effect on the structure and composition of titanate nanotubes and further affected the state and redox property of cerium oxides. The structure of TNTs-1.6, TNTs-7, and TNTs-12 were identified as anatase-like structure, protonated titanate (H2Ti3O7), and Na-containing titanate, respectively. Indeed, the residual sodium (TNTs-12) was harmful to ceria, but the presence of water in the interlayer (TNTs-7) was beneficial to the stability of nanotube structure. Therefore, TNTs-7 doped ceria showed the best SCR activity among these tested samples. (C) 2012 Elsevier Inc. All rights reserved.