Facile Synthesis of Ag@Pd_nL Icosahedral Nanocrystals as a Class of Cost-Effective Electrocatalysts toward Formic Acid Oxidation

We report a facile synthesis of Ag@Pd core−shell icosahedral nanocrystals for the development of cost-effective electrocatalysts toward formic acid oxidation. With 12.4 nm Ag icosahedra serving as seeds, Pd shells of controlled thicknesses in the range of 3.6–5.8 atomic layers are grown by adjusting the experimental parameters. When examined as catalysts toward formic acid oxidation, all the Ag@Pd nanocrystals exhibit enhanced mass activities relative to a commercial Pd/C catalyst, with the Ag@Pd_4.2L nanocrystals showing enhanced mass activity that is almost twice that of a commercial Pd/C. The chronoamperometry measurements indicate that all the Ag@Pd/C catalysts are more robust than the Pd/C, with the catalyst based on Ag@Pd_4.2L nanocrystals showing a mass activity greater than that of the pristine Pd/C after holding in a mixture of HCOOH and HClO₄ at 0.75 V for 1,000 s. We believe that the strategy demonstrated here can also be extended to the development of other types of advanced electrocatalysts.