Unveiling the nature and distribution of surface sites in heterogeneous catalysts, for Phillips catalyst (CrO3/SiO2) particular, is still a grand challenge despite more than 60 years research. Commonly used references Cr K-edge XANES spectral analysis rely on bulk materials (Cr-foil, Cr2O3) or molecules (CrCl3) that significantly differ from actual sites. In this work, we built library spectra ...

Magnetotransport measurements were made on patterned, ~110! oriented CrO2 thin films grown by the high-pressure, thermal decomposition of CrO3 onto rutile substrates. The low-temperature Hall effect exhibits a sign reversal from positive to negative as the magnetic field is increased above 1 T, which may be interpreted within a simple two-band model as indicating the presence of highly mobile (...

Stainless steels in atmospheres containing H2O form a Cr2O3 scale in the early stage of oxidation. However, the Cr2O3 scale gradually degrades with time. In order to determine the effect of H2O on the deterioration of a Cr2O3 scale, evaporation behavior of Cr2O3 in N2-O2-H2O atmospheres was investigated. The rate of mass loss in a N2-O2-H2O atmosphere was found to be one order of magnitude high...

The group 5-7 transition metal oxides (V2O5, CrO3, MoO3, WO3, and Re2O7) were anchored on a surface modified SiO2 support containing surface alumina, zirconia, and titania species prepared via incipient wetness impregnation of soluble precursors and calcination. The molecular and electronic structures of these “multilayered” supported M1Ox/M2Ox/SiO2 catalysts were characterized with in situ Ram...

The reliable analysis of highly toxic hexavalent chromium, Cr(VI), at ultra-trace levels remains challenging, given its easy conversion to non-toxic trivalent chromium. This work demonstrates a novel analytical method to quantify Cr(VI) at low ngL(-1) concentration levels in environmental water samples by using speciated isotope dilution (SID) analysis and double-spiking with Cr(III) and Cr(VI)...

High-throughput screening (HTS) methods based on topography gradients or arrays have been extensively used to investigate cell-material interactions. However, it is a huge technological challenge to cost efficiently prepare topographical gradients of inorganic biomaterials due to their inherent material properties. Here, we developed a novel strategy translating PDMS-based wrinkled topography g...

Chromium oxide (CrOx) cathode material (with chromium oxidation state of +5.3) was synthesized by thermal decomposition of chromium trioxide at high temperature and pressure in oxygen atmosphere. The duration of thermal decomposition had a significant effect on the performance of these materials in terms of lithiation capacity. The detrimental effect of CrO3 and lower oxidation state chromium o...