Effects of preparation method on exsolution and alloy formation in a PtRu bimetallic catalyst for hydrogen production via diesel reforming: Impregnation versus combustion synthesis

In diesel reforming, a catalyst is easily deteriorated by thermal sintering and coke formation. A proper preparation method improves stability by modifying the physicochemical properties of the catalyst. In this paper, the effects of preparation methods on exsolution and alloy formation in PtRu bimetallic catalysts for diesel reforming were studied. The catalysts were prepared by impregnation and combustion synthesis. The structure, surface morphology, and reduction characteristics of each catalyst were characterized by XRD, STEM, and H2-TPR. Based on these characterizations, the behavior of each catalyst in the reforming environment was identified by comparison of properties observed before and after the reaction. Pt and Ru individually crystallized from the impregnated catalyst, whereas Pt and Ru exsolved from the combustion synthesis catalyst to form a PtRu alloy. As a result, the combustion synthesis catalyst showed higher stability and coke resistance than the impregnated catalyst.