Effects of zirconia precursor on gold based samples for low temperature WGSR

1 wt% gold-loaded zirconia and sulphated zirconia prepared from two different precursors (ZrOCl(2)8H(2)O and ZrO(NO3)(2)6H(2)O) were tested in the low-temperature water gas shift reaction. Samples were characterized by nitrogen adsorption analysis, sulphur content analysis, atomic absorption, X Ray-diffraction analyses (XRD) and Temperature Programmed Reductions (TPR). XRD patterns indicated a high dispersion of gold on all the samples. A strong effect of zirconia precursor on surface area, on gold dispersion and on catalytic performances has been found. Catalysts synthesized by ZrOCl(2)8H(2)O precursor are more active and more stable than samples prepared by ZrO(NO3)(2)6H(2)O due to a stronger metal support interaction between gold nanoparticles and the "ex-chloride" zirconia support. Catalysts prepared on sulphated zirconia are more active and in particular more stable than catalysts supported on non-sulphated ones. On sulphated zirconia, the surface structural disorder left after sulphate removal, allows a lower mobility of gold atoms on the zirconia surface and therefore inhibits gold sintering