Structure and speciation of chromium ions in chromium doped Fe sub(2)O sub(3) catalysts

In this paper, we report a detailed characterisation of chromium doped iron oxide catalysts using a range of techniques to establish the nature of chromium species in the near surface and bulk of iron oxide, high-temperature shift (HTS) catalysts. In particular we have employed X-ray absorption spectroscopy Cr K-edge near edge and extended fine structure data for comparison with chemical and X-ray photoelectron spectroscopy. There was excellent agreement between the techniques in terms of identification and quantification of Cr super(6+) and Cr super(3+) species as a function of calcination temperatures between 100 and 500 degree C.