In situ topologically induced PtZn alloy @ ZnTiOx and the synergistic effect on glycerol oxidation

Abstract In this work, we prepared a PtZn@ZnTiOx/ZnTiO3 catalyst by using PtCl62−/ZnTi layered-double-hydroxide (LDH) as precursor and revealed the in-situ topological process through modulating the reduction conditions. The Cs-corrected HAADF-STEM and XAFS verified the formation of PtZn alloy structure and also indicated the generated ZnTiOx coating layer exhibited the feature of low-coordination. In glycerol oxidation, the obtained catalyst possessed obvious advantages in intrinsic activity and glyceric acid selectivity compared with bare PtZn alloy and Pt catalysts. Confirmed by O2-TPD and XPS analysis, the alloy effect with Zn and abundant oxygen vacancies in ZnTiOx layer could enhance the glycerol oxidation activity by promoting the oxygen activation. A series of FTIR analysis revealed that the enhanced selectivity was assigned to the low-coordination ZnTiOx at the interface, optimizing the intermediate glyceraldehyde adsorption form. Additionally, an excellent reusability with 76.2 % glycerol conversion and 61.3 % glyceric acid selectivity after 5 cycles was exhibited over PtZn@ZnTiOx/ZnTiO3 catalyst.