TEMPERATURE-PROGRAMMED REDUCTION OF SILICA-SUPPORTED PT/NI CATALYSTS STUDIED BY XANES

The reduction of bimetallic silica-supported Pt/Ni chloride catalyst precursors was followed by means of X-ray absorption spectroscopy. Quantitative analysis of the near-edge structures (XANES) of the Pt L(III) and the Ni K edge was used to follow the reduction kinetics of each metal phase. The reduction to the final material occurred in two steps: In the first, the reduction of Pt atoms and Ni atoms adjacent to Pt took place (forming a bimetallic phase); in the second, the reduction of the remaining Ni atoms occurred (forming a separate Ni phase). In the reduced bimetallic particles, XANES indicates electron transfer from Ni to Pt atoms compared to the monometallic particles.