Characteristics of MoO3 reduced with H2 at the different flow rates of H2

Article abstract of DOI:10.1246/bcsj.73.1029

MoO₃ was treated with H₂ at 623 K for 12 h. The degree of reduction and the specific surface area of H₂-reduced MoO₃ were dependent on the flow rate of H2 in the reduction process. MoO₃ with a surface area of about 5 m² g^-1 was transformed to a porous MoO(x) with a surface area of 180 m² g^-1 after reduction at a flow rate of H₂ larger than 600 ml min^-1 g^-1. The MoO(x) was found to be stable at 623 K, even in the presence of H₂O vapor. A study of reduction with a mixture of H₂ and H₂O showed that the degree of reduction and the surface area decreased with increasing partial pressure of H₂O in the reduction process. We conclude from these results that the reduction of MoO₃ to porous MoO(x) with a large surface area was prohibited by the action of H₂O produced by the reduction.