Study of the Relationship between Metal–Support Interactions and the Electrocatalytic Performance of Pt/Ti4O7 with Different Loadings

Abstract

The application potential of Pt/Ti4O7 has been reported, but the lack of research on the relationship between Pt loading, MSI, and catalytic activity hinders further development. Micron-sized Ti4O7 powders synthesized by a thermal reduction method under an H2 atmosphere were used as a support material for Pt-based catalysts. Using a modified polyol method, Pt/Ti4O7-5, Pt/Ti4O7-10, and Pt/Ti4O7-20 with different mass ratios (Pt to Pt/Ti4O7 is 0.05, 0.1, 0.2) were successfully synthesized. Uniformly dispersed platinum nanoparticles exhibit disparate morphologies, rod-like for Pt/Ti4O7-5 and approximately spherical for Pt/Ti4O7-10 and Pt/Ti4O7-20. Small-angle deflections and lattice reconstruction induced by strong metal–support interactions were observed in Pt/Ti4O7-5, which indicated the formation of a new phase at the interface. However, lattice distortions and dislocations for higher loading samples imply the existence of weak metal–support interactions. A possible mechanism is proposed to explain the different morphologies and varying metal–support interactions (MSI). With X-ray photoelectron spectroscopy, spectrums of Pt and Ti display apparent shifts in binding energy compared with commercial Pt-C and non-platinized Ti4O7, which can properly explain the changes in absorption ability and oxygen reduction reaction activity, as described in the electrochemical results. The synthetic method, Pt loading, and surface coverage of the support play an important role in the adjustment of MSI, which gives significant guidance for better utilizing MSI to prepare the target catalyst.