Marked addition effect of Re upon the water gas shift reaction over TiO2 supported Pt, Pd and Ir catalysts

Addition effect of Re on the water gas shift reaction over TiO2 supported Pt, Pd and Ir catalysts was studied, using a closed gas circulation system as well as an in situ infrared spectroscopy. Two different manners of enhancement effect were observed over these catalysts, (1) possible formation of bimetallic surface clusters with Re in the cases of Pt and Pd, (2) anchoring of nanoparticles by highly dispersed Re over TiO2 in the case of Ir. The FT-IR analyses of adsorbed species during WGS reaction exhibited that similar structure of catalytically active sites may be formed between Pt, Pd, or Ir metal and Re, which are effective for the activation of water and acceleration of WGS reaction.