Recyclable CeO2-ZrO2 and CeO2-TiO2 mixed oxides based Pt catalyst for aqueous-phase reforming of the low-boiling fraction of bio-oil

In this study, a series of CeO2-ZrO2 and CeO2-TiO2 materials with different composition were prepared, characterized by BET and XRD analysis, and their hydrothermal stability was studied by subjecting the samples to acetic acid solutions at 533 K. All of the materials, especially C1Z1 (50 mol% CeO2 with 50 mol% ZrO2) and C1T1 (50 mol% CeO2 with 50 mol% TiO2), exhibited excellent stability with no phase transformation and minimal decrease in their specific surface area (SSA) was observed even after 16 h. After being loaded by Pt, these catalysts were used for the aqueous phase reforming (APR) of the low-boiling fraction of bio-oil (LBF) to investigate their catalytic performance. Among these catalysts Pt/C1Z1 and Pt/C1T1 showed superior catalytic activity, probably due to their lowest reduction temperature and the largest amount of O vacancies generated by the reduction of the surface oxygen of well-dispersed CeO2. Thus, Pt/C1Z1 and Pt/C1T1 were chosen to investigate their recyclability. The catalytic activity and H2 selectivity of Pt/C1Z1 and Pt/C1T1 can be almost recovered after being calcined in air at 773 K for regeneration. After three cycles, the particle size of Pt/C1Z1 and Pt/C1T1 only experienced a slight increase, while for Pt/Al2O3 it increased from 2.9 nm to 7.8 nm. So, compared with Pt/Al2O3, the Pt/C1Z1 and Pt/C1T1 catalysts were identified as effective and recyclable candidates for the production of H2 rich fuel gas from APR of LBF.