High-Performance Catalytic PdZn and PdAg Films for the Semihydrogenation of 2-Methyl-3-Butyn-2-Ol in a Continuous-Flow Microreactor

The synthesis of an active, selective, and stable catalytic coating is a difficult task for the semihydrogenation of alkenols in a continuous-flow microreactor, being a potentially efficient strategy for the production of alkenols in fine organic synthesis. In this study, catalytic PdMe/TiO2 films (Me = Zn, Ag) were synthesized by the simple and efficient template sol-gel method and used in 2-methyl-3-butyn-2-ol semihydrogenation. The prepared bimetallic catalytic PdMe/TiO2 films (Me = Zn, Ag) demonstrated high catalytic selectivity due to the formation of PdZn and PdAg alloy nanoparticles (NPs). The surface of an active PdAg site is transformed under reaction conditions. The PdZn film demonstrated a better catalytic activity. Doping the support with zinc increases the selectivity and stability of the films. The analysis of X-ray photoelectron spectra shows that the zinc doped PdZn/Ti0.8Zn0.2O1.8 film has a higher concentration of active PdZn sites and a better oxidative stability as compared to PdZn/TiO2. The catalytic PdAg/TiO2 and PdZn/Ti0.8Zn0.2O1.8 demonstrated high stability in long-term experiments.