The Structural Evolution of the Molybdenum Trioxide Surface

1. Topographic AFM image of a freshly cleaved MoO3 (010) surface. The 4 x 4 micron area was imaged using a constant force of 2.5 nN. The steps in this region are oriented along the [001] direction. 2. Topographic AFM image of a MoO3 (010) surface which has reacted with 10% H2-N2 (with 20 ppm H2O) for 2 minutes. In this 1.9 x 1.9 micron image, small surface voids (black contrast), a 7 ang. step between layers, and 2 ang. steps associated with defects (the streaky contrast parallel to [001]) are all distinguished.
See R. L. Smith and G. S. Rohrer, "An Atomic Force Microscopy Study of the Morphological Evolution of the MoO3(010) Surface During Reduction Reactions", J. Catalysis, 163 (1996) 12, for details

1. Topographic AFM image of a MoO3 (010) surface after reaction with 10% H2-N2 (with 20 ppm H2O) for 2 min at 400 degC. 2. Topographic AFM image of a MoO3 (010) surface after reaction with 10% H2-N2 (with 20 ppm H2O) for 30s at 400 degC. Two small surface voids (the black contrast) are visible on the flat terrace.
See R. L. Smith and G. S. Rohrer, "An Atomic Force Microscopy Study of the Morphological Evolution of the MoO3(010) Surface During Reduction Reactions", J. Catalysis, 163 (1996) 12, for details

1. Topographic AFM image of a MoO3 (010) surface after treatment for 5 min at 400 degC in 10% H2 - N2 (with 20 ppm H2O.) Note the orientational order and high aspect ratio of the surface voids (black contrast) in this 4 x 4 micron image. 2. Topographic AFM image of a MoO3 (010) surface which was treated for 5 min at 400 degC in N2 which was saturated with water vapor at 25 degC. The steps are nearly parallel to <101>, an orientation rarely seen on fresh cleaved surfaces.
See R. L. Smith and G. S. Rohrer, "An Atomic Force Microscopy Study of the Morphological Evolution of the MoO3(010) Surface During Reduction Reactions", J. Catalysis, 163 (1996) 12, for details

evolution of surface voids during reoxidation in air at 400 degC. See R. L. Smith and G. S. Rohrer, "The Morphological Evolution of the MoO3-x(010) Surface During Reoxidation" in "Catalyst Materials for High Temperature Processes" (Ceram. Trans. 73, Westerville, OH, 1997), for details

evolution of the MoO3(010) surface during reaction with methanol at 400 degC