High-Temperature Synthesis of Small-Sized Pt/Nb Alloy Catalysts on Carbon Supports for Hydrothermal Reactions.

Catalytic biomass conversions are sustainable processes to produce value-added fuels and chemicals but need stable catalysts that can tolerate harsh hydrothermal conditions. Herein, we report a hydrothermally stable catalyst by alloying Pt with a high-melting-point metal Nb. The Pt/Nb alloy catalysts are prepared by H2 reduction at a high temperature of 900 °C with a high-surface-area carbon black support, which can suppress metal sintering at high temperatures and thus lead to small-sized alloyed Pt/Nb particles of only 2.2 nm. Taking the advantages of surface acid property provided by the Nb sites and the size effect, the prepared C-supported small-sized Pt/Nb alloy catalysts exhibit attractive activities for the hydrogenation of levulinic acid into γ-valerolactone and the water-gas shift reaction. More significantly, benefiting from the inherent stability of high-melting-point Nb, the Pt/Nb alloy catalysts show much enhanced hydrothermal stability compared to commercial Pt/C and Ru/C catalysts.