Understanding catalytic active-sites threshold of supported Pt catalysts for selective hydrogenation of phenol as a model compound for future biofuels

Catalytic transformation of bio-derived compounds to value-added chemicals and liquid fuels plays a significant role in biomass utilization and essentially depends on catalyst design. The active-sites threshold over Pt/ Ti3AlxC2Ty catalysts in selective hydrogenations (e.g., phenol and furfural) were identified, and XRD, TEM, XPS and FT-IR were conducted to analyze crystal structures, morphologies, chemical states, and adsorptive properties. The catalytic results of phenol hydrogenation demonstrated that the catalysts completely lost activity when Pt loading was 0.25 %wt. FT-IR analyses of phenol-adsorbed catalysts and supports showed that the threshold resulted from the massive adsorption of phenol molecules that occupied Pt active sites, suppressing H2 adsorption. By addition of Au nanoparticles, the phenol hydrogenation occurred over bimetallic Au0.8-Pt0.2/ Ti3AlxC2Ty, whereas merely Au nanoparticles were inactive for phenol hydrogenation. The findings could inspire peer researchers to design supported metal catalysts and regulate adsorption or interaction between catalyst surfaces and reactants.