Nitrate hydrogenation on Pt,In/Al2O3: EXAFS and XANES characterization of fresh and used catalysts

Pt,In/Al2O3 catalysts were characterized by EXAFS and XANES. Among the catalysts studied, the one that contained 1 wt.% of Pt and 0.25 wt.% of In had a remarkable high initial activity which decreased with reaction time. EXAFS characterization showed that the fresh solid consisted of a mixture of bimetallic Pt,In particles and monometallic Pt ones. After reaction, the amount of bimetallic particles decreased and unalloyed Pt considerably increased, which led to a partial deactivation of the catalyst.