Pd-Cu alloys have been widely utilized as catalysts for the hydrogenation of carbonyl compounds, for the reduction of nitrates and nitrites in water, for the oxidation of formic acid in direct formic acid fuel cell, as membrane for hydrogen separation and so on. In particular, bcc Pd-Cu alloys have occasionally shown superior performance to fcc Pd-Cu alloys. For an example of hydrogenation of acetylene, bcc Pd-Cu alloy have better ethylene selectivity than fcc Pd-Cu alloys, because isolated Pd atoms on the surface of bcc Pd-Cu alloys increase selectivity in the hydrogenation of acetylene. Most bcc Pd-Cu alloys have been synthesized by annealing of fcc Pd-Cu alloys, which leads to structural transformation and particle growth. Obtaining same sizes of fcc and bcc Pd-Cu alloys is difficult to achieve because crystallites larger than 20 nm favour the ordered bcc structure with lower symmetry. Thus, bcc Pd-Cu alloys in nanoscale have been rarely reported moreover, comparison of fcc and bcc Pd-Cu in nanoscale has been never demonstrated to date.

In this study, we successfully synthesized fcc and bcc Pd-Cu alloys in nanoscale by polyol process with same composition and particle size, furthermore we adopt fcc and bcc Pd-Cu alloys as cathode catalysts for lithium-oxygen batteries. This work would be the first time to compare the catalytic activities between fcc and bcc Pd-Cu alloys in nanoscale.