The synthesis of shape-, facet-, and composition-controlled Pd-based nanocrystals and the study of their catalytic reaction mechanisms are significant to and challenging for the development of advanced catalysts applicable to direct liquid-fuel cells (DLFCs). In the present study, we prepared (100)-faceted β-PdH cubes and ( 111)faceted β-PdH octahedra, which offered the opportunity to investigate the link between catalytic performance and the shape/facet/composition of nanocrystals. The β-PdH cubes and octahedra remarkably boosted catalytic activity and stability to the formic acid/methanol oxidation reaction (FAOR/MOR), due to the ligand effect originating from the interstitial alloying of β-PdH. Notably in this regard, β-PdH cubes exhibited the highest FAOR/MOR activity among Pdbased catalysts, owing to the relatively high CO tolerance on the Pd(100) facets. Our results confirm that simultaneous control of ligand and facet effects is an effective approach to the design of catalysts suitable for liquid fuel oxidation electrocatalysis.

Controlling the morphology and composition of nanocatalysts constructed from metals and conductive polymers has attracted attention owing to their great potential for the development of high‐efficiency catalysts for various catalytic applications. Herein, a facile synthetic approach for ultrathin‐polyaniline‐coated Pt–Ni nanooctahedra (Pt‐Ni@PANI hybrids) with controllable PANI shell thicknesses is presented. Pt–Ni nanooctahedra/C catalysts enclosed by PANI shells with thicknesses from 0.6 to 2.4 nm were obtained by fine control over the amount of aniline. The various Pt‐Ni@PANI hybrids exhibited electrocatalytic activity toward the methanol oxidation reaction that is highly dependent on the thickness of the PANI shell. Pt‐Ni@PANI hybrids with the thinnest PANI shells (0.6 nm) showed markedly improved electrocatalytic performance for the methanol oxidation reaction compared with Pt‐Ni@PANI hybrids with thicker PANI shells, Pt–Ni nanooctahedra/C, and commercial Pt/C due to synergistic benefits of ultrathin PANI shells and Pt–Ni alloy.

A facile synthesis method for shape-controlled Pd NC–PANI core–shell heteronanostructures with controllable PANI thickness for efficient electrochemical ethanol oxidation.

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Surface morphology‐dependent electrocatalytic performance of Pt‐Pd alloy nanocrystals with bumpy shape.

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Highly porous Au–Pt urchin-like bimetallic nanocrystals have been prepared by a one-pot wet-chemical synthesis method. The porosity of urchin-like bimetallic nanocrystals was controlled by amounts of hydrazine used as reductant. The prepared highly porous Au-Pt urchin-like nanocrystals were superior catalysts of electrochemical methanol oxidation due to high porosity and surface active sites by their unique morphology. This approach will pave the way for the design of bimetallic porous materials with unprecedented functions.

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