Shape-controlled Pd nanocrystal–polyaniline heteronanostructures with modulated polyaniline thickness for efficient electrochemical ethanol oxidation

Abstract

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.