Shape-controlled Pd nanostructure catalysts for highly efficient electrochemical power sources

We report polygonal Pd catalysts on carbon black synthesized by means of polyol process in the presence of poly(vinyl pyrrolidone) and NO3− ion. We find that the polygonal Pd/C has dominant {1 1 1} facets observed by X-ray diffraction method and transmission electron microscopy analysis. The current density for formic acid electrooxidation of polygonal Pd/C (1.908 mA cm−2) with controlled surface structures such as dominant {1 1 1} facets is much higher than Pd/C (0.478 mA cm−2) at 0 V. Furthermore, the polygonal Pd/C with controlled surface structures shows much improved performances in dye-sensitized solar cells (DSSCs) due to its highly thermal stability and enhanced catalytic activity for iodide reduction.