Shape-Controlled Pd Nanocrystal-Polyaniline Heteronanostructures with Modulated Polyaniline Thickness for Efficient Electrochemical Ethanol Oxidation

Constructing metal nanocrystal (NC)-polymer heteronanostructures (HNSs) with excellent properties in terms of ethanol adsorption and activation will lead to catalysts with a significantly enhanced electrochemical ethanol oxidation reaction (EOR). Herein, we present a facile and effective synthesis method for shape-controlled Pd NC-polyaniline (PANI) HNSs with various PANI thicknesses, which are achieved by using cubic and octahedral Pd NCs as metal NC seeds. By investigating the electrocatalytic properties of various Pd NC-PANI HNSs and their counterparts, we found that the electrocatalytic properties of the Pd NC-PANI HNSs highly depend on both the exposed facets of Pd NCs and thickness of the PANI coating. The cubic Pd NC-PANI (Pd-cube-PANI) HNSs with cubic Pd NCs and a 0.7 nm PANI coating significantly improved the electrocatalytic performance for the EOR compared to the Pd-cube-PANI HNSs with different PANI coating thicknesses, octahedral Pd NC-PANI (Pd-octa-PANI) HNSs with octahedral Pd NCs, cubic Pd NCs, and commercial Pd/C because of synergistic advantages of the favorable exposed facet and optimal PANI coating thickness.