Highly effective PdCu electrocatalysts supported on polyelectrolyte functionalized titanium dioxide for direct formic acid fuel cells

Abstract

A highly efficient and CO tolerant PdCu electrocatalysts supported on amino-rich, cationic poly(diallyl dimethyl ammonium chloride)(PDDA) functionalized TiO2 (PdCu/TiO2(P)-C) has been developed. The catalysts were characterized by transmission electron microscopy (TEM),X-ray diffraction (XRD),cyclic voltammograms and chronoamperometry. The PtCu particles with average size ~3.5 nm are well dispersed on TiO2(P). PdCu/TiO2(P)-C catalysts exhibit a superior electrocatalytic activity and stability for the formic acid oxidation reaction compared with the Pd/TiO2(P)-C . Electrochemical measurements indicate that PdCu/TiO2(P)-C(1:2) catalyst has the best performance for formic acid electro-catalytic oxidation in terms of durability and Pd-mass activity among three catalysts (Pd1Cu1,Pd1Cu2,Pd1Cu3). The possible reason is that the addition of Cu is beneficial to lower appropriately the d-band center of Pd and increase the electrochemical active surface area of the PdCu/TiO2(P)-C nanocatalysts, but when the content of Cu rises to a certain extent, the morphology of the catalyst nanoparticles will transform into linear structure leading to increased particle size.