Ru catalysts supported on activated carbon obtained by hydrothermal treatment of rice husk were evaluated in the hydrogenation reaction of levulinic acid to γ-valerolactone. The hydrothermally treated carbon was characterized by nitrogen physisorption, elemental analysis, and thermogravimetric analysis, and the catalysts were characterized by FTIR spectroscopy, X-ray photoelectron spectroscopy, temperature-programmed reduction, and temperature-programmed desorption of pyridine (acidic properties). Prior to the reaction, the catalysts were reduced at different temperatures in the range of 100–350 °C to evaluate the effect of the reduction temperature on the performance in the hydrogenation of levulinic acid. The reaction was carried out in a batch reactor at 70 °C and 1.5 MPa. The results of conversion and selectivity to γ-valerolactone showed that the catalyst with the best performance was the sample reduced at 200 °C. After 2 h of reaction, a γ-valerolactone yield of 74% was achieved. This catalyst presented the lowest acidity value, and the ruthenium-containing phase consisted mainly of RuO₂, with a small portion of Ru⁰. The solid catalyst can be recovered and successfully reused for three runs with the GVL yield at 56%.

Monometallic Pt catalysts (17%wt) were prepared over Vulcan carbon (VC) and multiwall carbon nanotubes (NT). These supports were functionalized with citric or nitric acid. The characteristics of the different functionalized and non-functionalized supports were analyzed to determine the influence of the functional groups over the electrocatalytic behavior of the Pt monometallic catalyst. The functionalization treatment with nitric acid increases the concentration of strong and weak functional groups, whereas citric acid promotes the formation of acid groups with intermediate acidic strength. Catalysts prepared by conventional impregnation (CI) and supported on functionalized VC and NT display much higher electrochemical active areas than those supported on the corresponding non-functionalized carbons. Both the decrease of the metallic particle sizes and the changes in the metal-support interaction due to the presence of the functional groups would lead to a better electrochemical behavior.