Preparation of Au@Pd Core–Shell Nanorods with fcc-2H-fcc Heterophase for Highly Efficient Electrocatalytic Alcohol Oxidation

Abstract

Controlled construction of bimetallic nanostructures with a well-defined heterophase is of great significance for developing highly efficient nanocatalysts and investigating the structure-dependent catalytic performance. Here, a wet-chemical synthesis method is used to prepare Au@Pd core−shell nanorods with a unique fcc-2H-fcc heterophase (fcc: face-centered cubic; 2H: hexagonal close-packed with a stacking sequence of "AB"). The obtained fcc-2H-fcc heterophase Au@Pd core−shell nanorods exhibit superior electrocatalytic ethanol oxidation performance with a mass activity as high as 6.82 A mg Pd −1 , which is 2.44, 6.96, and 6.43 times those of 2H-Pd nanoparticles, fcc-Pd nanoparticles, and commercial Pd/C, respectively. The operando infrared reflection absorption spectroscopy reveals a C2 pathway with fast reaction kinetics for the ethanol oxidation on the prepared heterophase Au@Pd nanorods. Our experimental results together with density functional theory calculations indicate that the enhanced performance of heterophase Au@Pd nanorods can be attributed to the unconventional 2H phase, the 2H/fcc phase boundary, and the lattice expansion of the Pd shell. Moreover, the heterophase Au@Pd nanorods can also serve as an efficient catalyst for the electrochemical oxidation of methanol, ethylene glycol, and glycerol. Our work in the area of phase engineering of nanomaterials (PENs) opens the way for developing highperformance electrocatalysts toward future practical applications.

Preparation of Amorphous SnO2‐Encapsulated Multiphased Crystalline Cu Heterostructures for Highly Efficient CO2 Reduction

“…Specifically, a series of unconventional hcp phases, including 2H with a stacking sequence of “AB”, 4H with a stacking sequence of “ABCB”, and 6H with a stacking sequence of “ABCACB”, can be observed in the Cu core (Figure 2f,g and Figure S3, Supporting Information). It is worth mentioning that the crystalline/amorphous [ 19–22 ] and crystalline/crystalline [ 14,23–25 ] heterophase structures could dramatically modulate the catalytic activity and selectivity. The measured lattice distance in the fcc domains of the Cu core is 0.21 nm (Figure 2f), corresponding to the (111) planes of fcc Cu.…”

One-Pot Aqueous Synthesis of Porous Hollow PdCu Alloy Nanoparticles for Enhanced Ethanol Electrooxidation

“…or nonmetal (P, B, etc.) is one of the most effective strategies to facilitate the removal of poisoning CH 3 CO ads by directly weakening the adsorption of CH 3 CO ads on Pd (Pd–CH 3 CO ads ) and optimizing the adsorption of OH ads on secondary metal/nonmetal (MOH ads ). − Such electronic and bifunctional effects have synergistically boosted EOR performance accordingly. Generally, Pd-based alloys are crystallographically face-centered cubic (fcc), favoring the synthesis of symmetric nanoparticles (NPs).…”

Boosting Hydrogen Production by Selective Anodic Electrooxidation of Ethanol over Trimetallic PdSbBi Nanoparticles: Composition Matters

“…The downshift of the d-band center relieves the over-binding of the intermediates on Pd active sites, thus accelerating the desorption of poisoning intermediate species on the catalyst surface. Besides, it is recognized that the rate-determining step of the reactive-intermediate pathway for Pd-based catalysts in alkaline media is the conversion of (CH 3 CO) ads to CH 3 COOH. − In this step, a higher adsorption ability of OH – on the catalyst surface can accelerate the reaction with acetyl to produce acetic acid . As shown in Figure e and Figure S15, the adsorption energy of OH – was decreasing with the x increasing for Pd 48 Sb 16‑ x Bi x .…”