Pd Shell Research Articles

One-step green synthesis of Au@Pd concave nanocubes in deep eutectic solvents and their highly catalytic activities for selective hydrogenation

Concave nanomaterials possess superior properties, but their synthesis usually requires complicated steps, specific conditions and additional reagents (surfactants, capping agents, seeds, etc.). Herein, the well-defined Au@Pd concave nanocubes (CNCs) is facile one-step fabricated in a deep eutectic solvent (DES, named reline) composed of choline chloride (ChCl) and urea. It is found that the reline is crucial to the formation of Au@Pd CNCs. Owing to the concave core-shell structures, and electronic effects between Au core and Pd shell, Au@Pd CNCs exhibited excellent catalytic performance, and recovery convenience in the selective hydrogenation of 4-nitrostyrene. Specifically, under normal temperature and pressure conditions (25°C, 0.1 MPa), 4-nitrostyrene can be completely hydrogenated to 4-nitroethylbenzene within 7.0 min. After five cycles, Au@Pd CNCs still maintain the highly catalytic activity and 100 % selectivity toward 4-nitroethylbenzene. It is expected that well-constructed Au@Pd CNCs also display advanced potentials in other applications.

Core-shell structured composite high-efficiency catalyst Co@Pd/TiO2 with a compressed-strain Pd shell for the direct synthesis of H2O2

Direct synthesis of H2O2 from H2 and O2 still faces the dilemma of low selectivity and productivity due to the O-O bond dissociation. To expedite the resolution of this issue, we introduce a core–shell structured catalyst Co@Pd/TiO2 with a compressed-strain Pd shell. The Co@Pd/TiO2 catalyst demonstrates a superior H2O2 productivity of 6.95 × 103 mmol·gPd-1·h−1 and H2O2 selectivity of 98.1 %, with enhancements of over 192 % and 139 %, respectively, when compared to Pd/TiO2. The construction of the compressed-strain Pd shell on the Co@Pd/TiO2 catalyst induces a winder width (wd) and a lower center (εd) of the Pd d-band, allowing the Co@Pd/TiO2 catalyst to achieve the following benefits for improving H2O2 selectivity and productivity: (1) Reducing the degree of electron back-donation to O2* (* denotes adsorbed state, the same below), thus inhibiting the cleavage of the O-O bond in O2*; (2) Showing a weaker Pd-O bond strength, which stabilizes the OOH* species and suppresses the breakage of the O-O bond therein; (3) Weakening the interaction between the catalyst and chemical substances, thereby restraining H2O2 degradation.

Atomic-scale strain engineering of atomically resolved Pt clusters transcending natural enzymes

Strain engineering plays an important role in tuning electronic structure and improving catalytic capability of biocatalyst, but it is still challenging to modify the atomic-scale strain for specific enzyme-like reactions. Here, we systematically design Pt single atom (Pt1), several Pt atoms (Ptn) and atomically-resolved Pt clusters (Ptc) on PdAu biocatalysts to investigate the correlation between atomic strain and enzyme-like catalytic activity by experimental technology and in-depth Density Functional Theory calculations. It is found that Ptc on PdAu (Ptc-PA) with reasonable atomic strain upshifts the d-band center and exposes high potential surface, indicating the sufficient active sites to achieve superior biocatalytic performances. Besides, the Pd shell and Au core serve as storage layers providing abundant energetic charge carriers. The Ptc-PA exhibits a prominent peroxidase (POD)-like activity with the catalytic efficiency (Kcat/Km) of 1.50 × 109 mM−1 min−1, about four orders of magnitude higher than natural horseradish peroxidase (HRP), while catalase (CAT)-like and superoxide dismutase (SOD)-like activities of Ptc-PA are also comparable to those of natural enzymes. Biological experiments demonstrate that the detection limit of the Ptc-PA-based catalytic detection system exceeds that of visual inspection by 132-fold in clinical cancer diagnosis. Besides, Ptc-PA can reduce multi-organ acute inflammatory damage and mitigate oxidative stress disorder.

Synthesis and catalytic activity of core-shell gold-palladium nanoworms towards the catalytic reduction of 4-nitrophenol and methyl orange

The Au-Pd core–shell nanostructures have gained attention as a promising catalyst and exhibit outstanding stability and selectivity in pivotal chemical reactions. This work demonstrates a facile seed-mediated approach for depositing the shell of Pd on worm-shaped Au nanostructures. The control over Pd content on Au nanoworms (NWs) was achieved by adjusting the concentration of tetrachloropalladic acid (H2PdCl4) in the deposition solution. The bent morphology, surface roughness, and polycrystalline structure of the Au NWs ensured that at lower H2PdCl4 concentrations, Pd formed an island-like structure on the Au NWs’ surface. In contrast, increasing the H2PdCl4 concentration led to the formation of a complete Pd shell encasing the Au NWs. The catalytic activity of the Au-Pd core–shell (Pd@Au) NWs exhibited a significant improvement compared to uncoated Au NWs, which has been attributed to the synergetic effect of the two metals. However, it was observed that an optimum Pd-coating was necessary to obtain the best catalytic performance and a further increase in Pd content led to the degradation of the catalytic activity. Specifically, the rate constant of the reduction reactions of 4-nitrophenol (4-NP) and methyl orange (MO) was increased by 6.3 and 3.1 folds, respectively, for the optimized Pd@Au NWs.

Elucidating refractive index sensitivity on subradiant, superradiant, and fano resonance modes in single palladium-coated gold nanorods

Herein, we investigated the distinctive scattering properties exhibited by single gold nanorods coated with palladium (AuNRs@Pd), with variations in the Pd shell thicknesses and morphologies. AuNRs@Pd were synthesized through bottom-up epitaxial Pd growth using two different concentrations of Pd precursor. These single AuNRs@Pd displayed the characteristic of subradiant and superradiant localized surface plasmon resonance peaks, characterized by a noticeable gap marked by a Fano dip. We revealed the effect of local refractive index (RI) on the subradiant and superradiant peak energies, as well as the Fano dip in the scattering spectra of AuNRs@Pd with different Pd shell thicknesses. We demonstrated the applicability of the inflection points (IFs) method on detecting peaks and dip changes across different RIs. Thin AuNRs@Pd1mM displayed more pronounced sensitivity to peak shifts in response to variations in local RIs compared to thick AuNRs@Pd2mM. In contrast, thick AuNRs@Pd2mM exhibited greater sensitivity to changes in curvature near the subradiant and superradiant peak energies rather than peak shift sensitivity across different local RIs. Moreover, the Fano dip shift was more noticeable in thick AuNRs@Pd2mM compared to thin AuNRs@Pd1mM across different local RIs. Therefore, we provided new insight into the RI sensitivity on subradiant, superradiant, and Fano resonance modes in single AuNRs@Pd.

Designing nanoporous Pd catalyst with dual enhancement of thermodynamics and kinetics for formic acid oxidation reaction

Conventional strategies for developing highly efficient electrocatalysts involve enhancing thermodynamics to minimize overpotential and improving kinetics to maximize reaction current. However, current research on Pd-based catalysts for formic acid oxidation reaction (FAOR) mainly focuses on accelerating its kinetics to increase the peak current. This study proposes a catalyst design that can simultaneously improve the kinetics and thermodynamics of FAOR. Specifically, the home-made catalyst (NPG-Pt1-Pd1) is obtained by sequentially depositing monolayer Pt and Pd shells on the surface of nanoporous gold (NPG) substrate. Compared with commercial Pd/C, this electrocatalyst exhibits a noticeable negative shift in onset potential (∼100 mV) and a significantly improved peak current (∼6 times). Experimental data and theoretical calculations demonstrate that NPG-Pt1-Pd1 exhibits a comparatively suitable adsorption energy for small molecules, not only reducing the overpotential but also accelerating the reaction rate of FAOR. Moreover, when applied in direct formic acid fuel cells (DFAFC), the NPG-Pt1-Pd1 anode with an exceptionally low Pd loading of 8.5 μg cm−2, achieves a remarkable power density of 141 mW cm−2. The power efficiency of Pd is 230 times that of Pd/C (1 mg cm−2, 73 mW cm−2). Therefore, this work provides a new methodology for developing efficient Pd-based FAOR electrocatalysts.

Facile construction of core-shell AuPd nanochain networks in one-pot for ethanol oxidation

Palladium (Pd)-based catalysts have been extensively investigated in direct ethanol fuel cells (DEFCs) since the urgent energy and environmental problems. Rational design Pd-based catalyst with outstanding structure can optimize its electrocatalytic performance for ethanol oxidation reaction (EOR) catalyst. In this work, a facile strategy was proposed to prepare AuPd nanochain networks (NNWs) with core-shell structure by adjusting the reduction rate by slowly dropping the acidic reducing agent to the alkaline precursor solution system. The resulting catalysts exhibit a porous self-supporting structure with twisted features, exposing a large number of active sites. The optimized AuPd NNWs catalyst displays much-improved activity (3289.62 mA mg−1 Pd) and greatly enhanced electrocatalytic stability for EOR in comparison with that of commercial Pd/C catalysts. This enhanced activity can be attributed to the synergic effect of the Pd shell with the Au core as well as the twisted and self-supporting structure which can expose much more active sites and provide rich mass and electron transfer channels.

Data-driven stabilization of NimPdn-m nanoalloys: a study using density functional theory and data mining approaches.

Green hydrogen, generated through the electrolysis of water, is a viable alternative to fossil fuels, although its adoption is hindered by the high costs associated with the catalysts. Among a wide variety of potential materials, binary nickel-palladium (NiPd) systems have garnered significant attention, particularly at the nanoscale, for their efficacious roles in catalyzing hydrogen and oxygen evolution reactions. However, our atom-level understanding of the descriptors that drive their energetic stability at the nanoscale remains largely incomplete. Here, we investigate by density functional theory calculations the descriptors that drives the stability of the NimPdn-m clusters for different sizes (n = 13, 27, 41) and compositions. To achieve our goals, a large number of trial configurations were generated and selected using data mining algorithms (k-means, t-SNE) and genetic algorithms, while the most important physical-chemical descriptors were identified using Spearman correlation analysis. We have found that core-shell formation, with the smaller Ni atoms lying in the center of the particle, plays a major role in the stabilization of the nanoalloys, and this effect causes the alloys to assume a icosahedral-fragment configuration (as the unary nickel cluster) instead of a fcc fragment (as the unary palladium cluster). However, the core-shell formation in this alloy is unique in that Pd poor compositions exhibit scattered Pd atoms on the surface. As the palladium content increases, this gives rise to the complete Pd shell. This stabilization mechanism is quantitatively supported by the different correlations observed in the number of Ni-Ni and Pd-Pd bonds with energy, in which the latter tends to decrease alloy stability. Furthermore, a notable trend is the correlation between the coordination number of Ni atoms with alloy stabilization, while the coordination of Pd atoms shows an inverse correlation.

Core–shell Pd(0)@His-SiO2/CoFe2O4 nano-composite as a magnetically recoverable heterogeneous catalyst for the deprotection of oximes and Heck coupling

Rational engineering of core–shell nanostructure-based catalysts have received significant attention owing to their potential for exhibiting unique properties such as durability, structural flexibility, and porous shell adaptability.

Nanosized Pd@Ag heterojunction with tunable shapes: Morphological modulation for improving plasma-mediated catalytic hydrogen evolution

Catalytic ability of bi-metal hybrid nanoagents largely depends on their phase constitution and morphology, also bearing a close correlation to the fabrication process. We herein design and develop a modified polyol protocol with inorganic ion induction for rationally constructing Ag nanoagents with tunable shapes (nanowire, nanocube, and nanoparticle), followed by evenly anchoring of stepwise reduced Pd nanograins on the surface of Ag nanoagents to foster Ag core - Pd shell (i.e. Pd@Ag) nanosized heterostructure. A home-made photochemical reaction device is used to scientifically evaluate the catalytic ability of the Pd@Ag nanoagents on hydrolyzing ammonia borane to evolve hydrogen gas. The ample characterization reveals that the fabricated Ag nanoagents hold the expected regular and uniform shapes, with 10–15 nm thick Pd layer cladded on their surfaces. The particular shapes of the Ag nanoagents can be duly manipulated via the induction of inorganic ions, and the thickness and compactness of the Pd shell can also be suitably regulated by controlling reduction duration. The verified formation of electron synergistic effect among the both metals is favorable to elevate the catalytic ability. The bimetal Pd@Ag nanoagents perform the superior catalytic activity under visible light irradiation, far exceeding that of the respective monometal counterparts, with the order of catalytic activity: Pd@Ag-NWs > Pd@Ag-NCs > Pd@Ag-NPs. The hydrolysis reaction at the given conditions is confirmed to be quasi first-order reaction, with the apparent activation energy of 53.44 kJ·mol−1 and TOF value of 47.04 min−1. The Pd@Ag-NWs catalyst behaves satisfactory stability, with 87.8 % initial catalytic activity retained after five cyclic use.

Enabling Pd Catalytic Selectivity via Engineering Intermetallic Core@Shell Structure.

Core@shell nanoparticles (NPs) have been widely explored to enhance catalysis due to the synergistic effects introduced by their nanoscale interface and surface structures. However, creating a catalytically functional core@shell structure is often a synthetic challenge due to the need to control the shell thickness. Here, we report a one-step synthetic approach to core-shell CuPd@Pd NPs with an intermetallic B2-CuPd core and a thin (∼0.6 nm) Pd shell. This core@shell structure shows enhanced activity toward selective hydrogenation of Ar-NO2 and allows one-pot tandem hydrogenation of Ar-NO2 to Ar-NH2 and its condensation with Ar-CHO to form Ar-N═CH-Ar. DFT calculations indicate that the B2-CuPd core promotes the Pd shell binding to Ar-NO2 more strongly than to Ar-CHO, thereby selectively activating Ar-NO2. The chemoselective catalysis demonstrated by B2-CuPd@Pd can be extended to a broader scope of substrates, allowing green chemistry synthesis of a wide range of functional chemicals and materials.

Facile Synthesis of Multifunctional Ni(OH)2-supported Core-shell Ni@Pd Nanocomposites for the Electro-oxidation of Small Organic Molecules.

In the domain of proton exchange membrane fuel cells (PEMFCs), the development of efficient and durable catalysts for the electro-oxidation of small organic molecules, especially of alcohols (methanol, ethanol, ethylene glycol, et al.) has always been a hot topic. A large number of related electrocatalysts with splendid performance have been designed and synthesized till now, while the preparation processes of most of them are demanding on experimental operations and conditions. Herein, we put forward a facile and handy method for the preparation of multifunctional Ni(OH)2-supported core-shell Ni@Pd nanocomposites (Ni(OH)2/Ni@Pd NCs) with the assistance of galvanic replacement reaction (GRR) at room temperature and ambient pressure. As expected, the Ni(OH)2 substrate can prevent the aggregation of core-shell (CS) Ni@Pd nanoparticles (NPs) and inhibit the formation of COads and further prevent Pd from being poisoned. The synergistic effect between CS Ni@Pd NPs and Ni(OH)2 substrate and the electronic effect between Pd shell and Ni core contribute to the outstanding electrocatalytic performance for methanol, ethanol, and ethylene glycol oxidation in alkaline condition. This study provides a succinct method for the design and preparation of efficient Pd-based electrocatalysts for alcohol electro-oxidation.

Surface reconstruction enabled o-PdTe@Pd core-shell electrocatalyst for efficient oxygen reduction reaction

Palladium-based alloy catalysts have been employed as one of the potential candidates for oxygen reduction reaction (ORR), but the dissolution of transition metal hinders their application. Herein, structure ordered PdTe intermetallic with Pd shell (o-PdTe@Pd) are synthesized via an electrochemical etching driven surface reconstruction strategy. The surface reconstruction could tune the electronic structure, weaken the adsorption energy of reaction intermediates on o-PdTe@Pd, resulting in enhanced electrocatalytic activity for ORR. The mass activity of o-PdTe@Pd is about 3.3 and 2.7 times higher than that of Pd/C in acid and alkaline, respectively. Besides, the half-potentials for ORR decay only about 44 mV and 12 mV after 30 k cycles accelerated durability test in acid and alkaline media, respectively. The enhanced durability originates from the resistance of Te atoms dissolve in the ordered PdTe intermetallic core and the core-shell structure. When assembled in a Zn-air battery, o-PdTe@Pd electrode delivers a higher specific capacity (794 mAh/g) and better cycling stability than Pt/C.

Theory of Hot-Carrier Generation in Bimetallic Plasmonic Catalysts.

Bimetallic nanoreactors in which a plasmonic metal is used to funnel solar energy toward a catalytic metal have recently been studied experimentally, but a detailed theoretical understanding of these systems is lacking. Here, we present theoretical results of hot-carrier generation rates of different Au-Pd nanoarchitectures. In particular, we study spherical core-shell nanoparticles with a Au core and a Pd shell as well as antenna-reactor systems consisting of a large Au nanoparticle that acts as an antenna and a smaller Pd satellite nanoparticle separated by a gap. In addition, we investigate an antenna-reactor system in which the satellite is a core-shell nanoparticle. Hot-carrier generation rates are obtained from an atomistic quantum-mechanical modeling technique which combines a solution of Maxwell's equation with a tight-binding description of the nanoparticle electronic structure. We find that antenna-reactor systems exhibit significantly higher hot-carrier generation rates in the catalytic material than the core-shell system as a result of strong electric field enhancements associated with the gap between the antenna and the satellite. For these systems, we also study the dependence of the hot-carrier generation rate on the size of the gap, the radius of the antenna nanoparticle, and the direction of light polarization. Overall, we find a strong correlation between the calculated hot-carrier generation rates and the experimentally measured chemical activity for the different Au-Pd photocatalysts. Our insights pave the way toward a microscopic understanding of hot-carrier generation in heterogeneous nanostructures for photocatalysis and other energy-conversion applications.

Elucidating Surface Plasmon Damping and Fano Resonance Induced by Epitaxial Growth of Palladium on Single Gold Nanorods.

Plasmon damping and Fano resonance induced in the growth of palladium (Pd) on gold nanorods (AuNRs) have been poorly understood. Herein, we investigated the optical properties and morphologies of single AuNRs@Pd (core@shell) synthesized using epitaxial Pd growth at different Pd concentrations. The localized surface plasmon resonance (LSPR) spectra of single AuNRs@Pd showed characteristic subradiant and superradiant peaks as well as Fano resonance as a spectral dip, which was highly influenced by the Pd shell thickness. The occurrence of the Fano resonance during the Pd growth was further verified by in situ real-time observation experiments. We then elucidated time-dependent, real-time variations in LSPR peak wavelength, metal-induced surface damping, and Fano resonance mode of single AuNRs@Pd during Pd shell formation in three successive phases: Pd reduction, nucleation, and growth. Therefore, this study provides new insights into metal interface damping, the Fano resonance, and optical tunability by engineering the Fano resonance energy and Pd shell thickness.

Oxygen Plasma Induced Nanochannels for Creating Bimetallic Hollow Nanocrystals.

Platinum-based metal catalysts are considered excellent converters in various catalytic reactions, particularly in fuel cell applications. The atomic structure at the nanocrystal surface and the metal interface both influence the catalytic performance, controlling the efficiency of the electrochemical reactions. Here we report the synthesis of Ag/Pt and Ag/Pd core/shell nanocrystals and insight into the formation mechanism of these bimetallic core/shell nanocrystals when undergoing oxygen plasma treatment. We carefully designed the oxidation treatment that determines the structural and compositional evolution. The accelerated oxidation-triggered diffusion of Ag toward the outer metal shell leads to the Kirkendall effect. After prolonged oxygen plasma treatment, most core/shell nanocrystals evolve into hollow spheres. At the same time, a minor fraction of the metal remains unchanged with a well-protected Ag core and a monocrystalline Pt or Pd shell. We hypothesize that the O2 plasma disturbs the Pt or Pd shell surface and introduces active O species that react with the diffused Ag from the inside out. Based on EDX elemental mapping, combined with several electron microscopic techniques, we deduced the formation mechanism of the hollow structures to be as follows: (I) the oxidation of Ag within the Pt or Pd lattice causes a disrupted crystal lattice of Pt or Pd; (II) nanochannels arise at the defect locations on the Pt or Pd shell; (III) the remaining Ag atoms pass through these nanochannels and leave a hollow crystal behind. Our findings deepen the understanding of interface dynamics of bimetallic nanostructured catalysts under an oxidative environment and unveil an alternative approach for catalyst pretreatment.

Porous silica supported Ag core-Pd shell composite: Seed-mediated stepwise reduction and tunable dispersion for boosting catalytic hydrogen evolution

For developing efficient and practical catalysts to achieve controllable hydrogen evolution from chemical hydrogen storage material, we herein demonstrate a seed-mediated stepwise reduction and tunable dispersion protocol to fabricate porous silica supported Ag core - Pd shell composites (Pd@Ag/SiO2) with serial metal molar ratios. By reasonable regulation for reduction sequence and growing conditions, the Pd@Ag bimetal layered nanostructure could be piloted to take orderly shape; via adjusting addition time and dosage for the reactants and additives, the resultant Pd@Ag nanoagents can be firmly attached on porous silica. The little by little assembled nanoagents with mean size of 10 nm on the silica microspheres construct a loose and porous secondary microstructure, leading to increment of specific surface area to some degrees. The generation of electron synergistic effect among the metals and carrier, verified by the XPS analysis, contributes to boosting the catalytic ability. The catalytic activity of the bimetal composites all exceed that of mono-metal composites, of which the bimetal composite Pd0.75@Ag0.25/SiO2 holds the top catalytic ability, even beyond that of Pd/SiO2 or Pd-NPs, followed by Pd0.5@Ag0.5/SiO2 and Pd0.25@Ag0.75/SiO2. The AB hydrolysis catalyzed by Pd0.75@Ag0.25/SiO2 at the given temperatures (293 to 313 K) is validated to be a first-order reaction, with apparent activation energy of 42.46 kJ·mol−1 and TOF value of 109.99 min−1. The catalyst Pd0.75@Ag0.25/SiO2 presents satisfactory stability, still retaining 83.2 % initial catalytic activity after five repeated use.

Synthesis and Structural Characterization of Branched Bimetallic AuPd Nanoparticles with a Highly Tunable Optical Response.

Bimetallic nanostructures composed of gold (Au) and palladium (Pd) have garnered increased interest for their applications in heterogeneous catalysis. This study reports a simple strategy for manufacturing Au@Pd bimetallic branched nanoparticles (NPs), which offer a tunable optical response, using polyallylamine-stabilized branched AuNPs as template cores for Pd overgrowth. The palladium content can be altered by manipulating the concentration of PdCl42- and ascorbic acid (AA) that are injected, which permit an overgrowth of the Pd shell up to ca. 2 nm thick. The homogeneous distribution of Pd at the surfaces of Au NPs can be carried out regardless of their size or branching degree, which allows for an adjustment of the plasmon response in the near-infrared (NIR) spectral range. As a proof of concept, the nanoenzymatic activity of pure gold and gold-palladium NPs was compared, exploring their peroxidase-like activity in the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB). The bimetallic AuPd NPs demonstrate an increase in the catalytic properties attributed to the presence of palladium at the surface of gold.

Dynamic tracking of exsolved PdPt alloy/perovskite catalyst for efficient lean methane oxidation

Supported Pd based catalysts are considered as the efficient candidates for low-carbon alkane oxidation for their outstanding capability to break C-H bond. Whereas, the irreversible deactivation of Pd based catalysts was still frequently observed. Herein, we reinforced the extruded Pd nanoparticles with quantitive Pt to assemble the evenly distributed PdPt nanoalloy onto ferrite perovskite (PdPt-LCF) matrix with strengthened robustness of metal/oxide support interface. We further co-achieved the enhanced performance, anti-overoxidation as well as resistance of vapor-poisoning in durability measurement. The operando X-ray photoelectron spectroscopy (O-XPS) combined with various morphology characterizations confirms that the accumulation of surface deep-oxidation species of Pd4+ is the culprit for fast activity loss in exsolved Pd system, especially at high temperature of 400 °C. Conversely, it could be completely suppressed by in-situ alloying Pd with equal amount of Pt, which helps maintain the metastable Pd2+/Pd shell and metallic solid-solution core structure. The density function theory (DFT) calculations further buttress that the dissociation of CH was facilitated on alloy/perovskite interface which is, on the contrary, resistant toward O–H bond cleavage, as compared to Pd/perovskite. Our work suggests that the modification of exsolved metal/oxide catalytic interface could further enrich the toolkit of heterogeneous catalyst design.

From AuPd Nanoparticle Alloys towards Core‐Shell Motifs with Enhanced Alcohol Oxidation Activity

AbstractThe best activity of bimetallic AuPd nanoparticles for alcohol oxidation reaction is usually achieved by adjusting the Au/Pd molar ratio. Herein, alloy AuPd nanoparticles of ∼2.5–3.5 nm, ranging from Au‐rich to Pd‐rich compositions, were synthesized through a sol‐immobilization method. A calcination step under air conditions caused an increase in size up to 5.5 nm, but also driven the segregation of Pd to the surface, which generated an Au rich core with Pd on the shell. At high Pd content, the shell structure is formed by PdO. The catalytic activity of Pd‐rich samples (1 : 1, 1 : 2 and 1 : 4 Au : Pd) for benzyl alcohol oxidation increased ∼4‐fold after calcination. Upon reduction with H2, surface PdO motifs are reduced to Pd that did not dissolve back into the AuPd alloy core, maintaining the metallic Pd shell. The catalytic activity decreased. Therefore, restructuring alloyed AuPd nanoparticles into core‐shell like structures with PdO in the shell is beneficial to the catalytic activity, but reduction of PdO layer was detrimental. These results provide new insights on the optimization of AuPd catalysts, considering not only the Au/Pd molar ratio, but also the importance of PdO, which was not anticipated in the previous literature.