Electrocatalysis of titanium suboxide-supported Pt-Tb towards formic acid electrooxidation

The Pt-Tb catalysts supported titanium suboxide (Ti4O7) with different amounts of Tb were synthesized by a simple simultaneous reduction reaction with sodium borohydride in aqueous solution. The structure and morphology of the catalysts were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM), and element valence states were investigated by X-ray photoelectron spectroscopy (XPS). Electrochemical characterization techniques, including cyclic voltammetry (CV), chronoamperometry (CA) and CO stripping were used to analyse the electrochemical performance of these catalysts for formic acid oxidation. The results revealed that the Pt-2.5%Tb/Ti4O7 catalyst has a significantly higher activity than the Pt/Ti4O7 catalyst. According to CO stripping results, the promotive effect of Tb can be explained by a bifunctional mechanism. Additionally, the analysis for XPS spectra indicates that the higher content of metallic Pt caused by the addition of Tb also contributes to the better catalytic activity of Pt-2.5%Tb/Ti4O7.