(729a) Deactivation and Regeneration of Carbon Supported Pt and Ru Catalysts in Aqueous Phase Hydrogenation of 2-Pentanone

Biomass conversion in the aqueous phase remains a challenge partly due to the instability of common heterogeneous catalysts under hydrothermal conditions. Deactivation mechanisms include structural collapse of the support and leaching and sintering of the supported metal particles have been reported as primary deactivation modes. Discussed will be results showing that carbon deposition can be a primary deactivation mode such as in the aqueous-phase hydrogenation of 2-pentanone on carbon supported platinum catalysts. Carbon deposition on the catalyst was confirmed by ATR-FTIR, NMR, TGA/DSC/FTIR analysis. Additionally, a mild in-situ regeneration method including air oxidation and hydrogen reduction at temperature lower than 200°C was developed that could fully recover the catalytic activity without affecting the catalyst negatively. Detailed analysis including HAADF-STEM, BET surface area, and CO chemisorption showed stable physical properties of the catalyst with only moderate sintering of metal particles under the hydrothermal conditions. The regeneration method was also successfully applied to Ru catalysts with full recovery of activity. The mild regeneration method likely has applicability to catalyst regeneration for other aqueous-phase biomass conversion reaction with oxygenated molecules.