Post-synthesis modification of goldsilver nanoparticles: a way to tune catalytic activity and selectivity

Carbon supported gold catalysts are highly active in the liquid phase oxidation of glycerol. In particular, bimetallic particles show enhanced activity, diverse selectivity and higher stability. Au–Ag catalysts supported on TiO2 by sequential deposition–precipitation method showed higher conversion than monometallic Au/TiO2 in CO oxidation, confirming the synergistic effect between Au and Ag. Moreover, the catalyst activation temperature influenced both the catalytic activity and nanoparticles composition. Theoretical studies investigating the segregation of Ag in Au-Ag NPs, reporting that segregation behaviors are composition, size and temperature dependent. Based on these facts and considering the already proven efficiency of Au-Ag bimetallic catalysts in glycerol oxidation, here we compared the catalytic activity and selectivity of differently synthesized and post-treated Au-Ag/TiO2 catalysts for glycerol oxidation. The same post-treatment had a different outcome on the nanoparticles features, and this reflected on the catalytic activity and selectivity.