A hierarchical heterostructure based on Pd nanoparticles/layered double hydroxide nanowalls for enhanced ethanol electrooxidation

Abstract

Finely dispersed Pd nanoparticles (PdNPs) anchored to CoAl layered double hydroxide nanowalls (LDH-NWs) have been fabricated via a facile in situ redox reaction between the LDH-NWs and the PdCl₄²⁻ precursor. The integrated LDH-NWs play the roles of both a hierarchical support and a reductant without any external agent, ensuring the cleanness of the metal–support interface. Based on the effective exposure of the Pd active sites and the elaborate network architecture, the Pd/LDH-NW heterogenous material yields a largely improved catalytic activity as well as robust durability towards ethanol electrooxidation in comparison with the commercial Pd/C catalyst. Moreover, a density functional theory (DFT) calculation indicates that the enhancement in the electrocatalytic properties originates from the synergistic effect between the metal and support, in which the LDH support stabilizes the PdNPs via the formation of a Pd–HO bond which is accompanied by an electron transfer from the LDH to the PdNPs. This work provides a promising approach for the design and fabrication of highly efficient metal-supported nanocatalysts which can be used in fuel cells and other related catalytic reactions.