Effect of the preparation method on the catalytic activity and stability of Au/Fe2O3 catalysts in the low-temperature water-gas shift reaction

The low temperature water-gas-shift reaction has been studied over a series of nanosized Au/Fe2O3 catalysts. The effect of the synthesis method on the catalytic activity has been analysed. A series of catalysts with different Au loadings has been prepared by different methods: deposition-precipitation (DP), liquid phase reductive deposition (LPRD) and double impregnation method (DIM). The Au/Fe2O3 catalysts prepared by DP showed the highest CO conversion. The catalysts were characterised by hydrogen temperature programmed reduction (TPR-H-2), high-resolution transmission electron microscopy (HRTEM), X-ray powder diffraction and X-ray photoelectron spectroscopy. TPR-H-2 analysis revealed that gold promotes the reducibility of the Fe2O3 support, which is crucial in this redox reaction. HRTEM evidences a very good dispersion of gold over the iron support, with nanoparticles in the range 2.2-3.1 nm for the DP and LPRD series, and a negligible increase in the average particle size of the used samples. For the DIM series, much larger Au particles (similar to 6.6 nm) were obtained. (C) 2013 Elsevier B.V. All rights reserved.