Pd NCs Research Articles

Spatial Confinement of Pd Nanoclusters in Pyrene-Based Covalent Organic Frameworks for Boosting Photocatalytic CO2 Reduction.

Photocatalytic CO2 reduction offers a promising strategy to mitigate the greenhouse effect, yet it remains a challenging process due to the high energy barrier associated with the high stability of CO2. In this study, we synthesized Py-bTDC, a pyrene-based covalent organic framework (COF) enriched with nitrogen and sulfur atoms, and anchored palladium nanoclusters (Pd NCs) onto its structure to enhance CO2 reduction efficiency. The confined Pd NCs amplify the built-in electric field (IEF), enabling efficient photogenerated carrier migration and suppressing electron-hole recombination. Simultaneously, Pd NCs serve as catalytic active sites, optimizing CO2 adsorption and activation. Density functional theory (DFT) calculations reveal that Pd reduces the energy barrier for forming the critical intermediate (*COOH), thereby accelerating CO production. Under visible-light irradiation in a gas-solid system using water as a proton donor, the Pd3/Py-bTDC composite achieved a CO evolution rate of 17.75 μmol·h-1·g-1 with 86.0% selectivity. This study advances the design of COF-based photocatalysts by synergistically modulating IEF and the engineering active sites for efficient CO2 reduction.

Palladium Nanocubes with {100} Facets for Hydrogen Evolution Reaction: Synthesis, Experiment and Theory.

Spatially separated palladium nanocubes (Pd NCs) terminated by {100} facets are synthesized using direct micelles approach. The stepwise seed-mediated growth of Pd NCs is applied for the first time. The resulting Pd NCs are thoroughly characterized by HR-TEM, XPS, Raman, ATR-FTIR, TGA, and STEM-EDX spectroscopies. Some traces of residual stabilizer (polyvinylpyrrolidone, PVP) attached to the vertices of Pd NCs are identified after the necessary separation-washing procedure, however, it is vital to avoid aggregation of the NCs. Pd NCs are subsequently and uniformly loaded on Vulcan carbon (≈20 wt.%) for the electrochemical hydrogen cycling. By post-mortem characterizations, it is revealed that their shape and size remained very stable after all electrochemical experiments. However, a strong effect of the NCs size on their hydrogen interaction is revealed. Hydrogen absorption capacity, measured as the H:Pd ratio, ranges from 0.28 to 0.48, while hydrogen evolution and oxidation reactions (HER and HOR) kinetics decrease from 15.5 to 4.6mA.mg Pd -1 between ≈15 and 34nm of Pd NCs, respectively. Theoretical calculations further reveal that adsorption of H atoms and their penetration into the Pd lattice tailors the NCs electronic structure, which in turn controls the kinetics of HER, experimentally observed by the electrochemical tests. This work may pave the way to the design of highly active electrocatalysts for efficient HER stable for a long reactive time. In particular, obtained results might be transferred to active Pd-alloy-based NCs terminated by {100} facets.

An “on-off” ratiometric electrochemiluminescence biosensor based on LSPR-enhanced by Ag@Au nanostructures combined with Pd NCs catalysing a single luminophore for MiRNA let-7a detection

An “on-off” ratiometric electrochemiluminescence biosensor based on LSPR-enhanced by Ag@Au nanostructures combined with Pd NCs catalysing a single luminophore for MiRNA let-7a detection

Supported palladium nanocubes reduced by graphene oxide and surface-cleaned for enhanced electrocatalytic activity

Supported palladium nanocubes reduced by graphene oxide and surface-cleaned for enhanced electrocatalytic activity

Atomically precise Pdm(SR)n nanoclusters for efficient hydrogen evolution reaction

Atomically precise Pdm(SR)n nanoclusters for efficient hydrogen evolution reaction

Quantitative Study on the Influence of Bromide Ions toward the Reduction Kinetics for Size-Tunable Palladium Nanocubes.

During the preparation of nanocrystals, regulating the dosage of key additives in the reaction system and the reaction temperature commonly affects the sizes and morphologies of the products. Despite the fact that bromide ions play a pivotal role in the synthesis of palladium nanocubes (Pd NCs), there is still a lack of quantitative and in-depth research on how the ions affect the reduction kinetics of Pd precursors and further on products. In this work, Pd NCs with different sizes have been prepared under various reaction conditions coupled to a systematic mechanism study. Quantitative measurements demonstrate that the reduction processes could be considered quasi-first-order reactions, and the corresponding kinetic parameters have been obtained. Furthermore, a linear relationship is discovered between k and the average size (d) of Pd NCs. The investigation on the growth patterns of four chosen systems reveals that given reaction conditions lead to certain results with unique growth patterns.

Systematic Study on the Precursor Reduction Kinetics and Growth Pattern for Size-Tunable Palladium Nanocubes.

Unveiling the underlying chemistry during the growth of well-defined nanocrystals is a fundamental but challenging task in materials chemistry. Herein, Pd NCs with tunable sizes ranging from 4.5 to 23.5 nm have been synthesized in the presence of potassium acetate (KOAc). The Pd precursor variation trends of these preparation systems along with reaction time have been determined using a UV-vis spectrometer, and corresponding reduction kinetic parameters, including the apparent reduction rate constant (k) and activation energy (Ea), are calculated by regarding the reduction processes as quasi-first-order reactions. It is confirmed that the introduction of KOAc does not affect the value of the Ea of different reaction systems. The interrelationship of k, product size (d), and reaction temperature (T) is discussed in depth. Results indicate that the three parameters are closely related, and for given reaction systems, they are specified. With the careful investigation of six specific systems (reaction systems with 10 mM, 20 mM KOAc at 55 °C, with 5 mM, 10 mM KOAc at 65 °C, without KOAc at 75 °C, and with 5 mM KOAc at 85 °C), the growth pattern of Pd NCs is described with an empirical expression and is further confirmed as a synergistic result of k and T.

Electrochemical Behavior and Shape Evolution of Structured Pd Nanoparticles in Alkaline Media─Influence of Electrochemically Absorbed Hydrogen.

We report on the electrochemical behavior and shape evolution of Pd nanocubes (Pd NCs) and Pd nanooctahedrons (Pd NOs) with an average size of 9.8 and 6.9 nm, respectively, in aqueous alkaline medium in the potential range of the underpotential deposition of H (UPD H) and H absorption. While the Pd NCs and Pd NOs remain stable in the potential region of the UPD H, H absorption and desorption of absorbed H (Habs) induce structural changes to the Pd NPs, as indicated by the results of electrochemical measurements and identical location-transmission electron microscopy (IL-TEM) analyses. Because both Pd NCs and Pd NOs are known to be stable in the potential region of H absorption and Habs desorption in acidic medium and maintain their structure, the irreversible structural changes are attributed to their interfacial interaction with the aqueous alkaline medium. In the alkaline medium, the nanoparticle surface/electrolyte interfacial structure plays an essential role in the mechanism of Habs desorption that is observed at higher potentials than that in the acidic medium. Hydrogen desorption is substantially hindered due to the structure of the water network adjacent to the Pd nanoparticles or the interaction between hydrated cations and adsorbed OH on the nanoparticle surface, resulting in the trapping of a small amount of H (incomplete Habs desorption). It is proposed that H trapping and associated structural strain lead to the deformation of the Pd nanoparticles and the loss of their initial structure.

Synergistic integration of few-layer thick MXenes and small Pd nanocubes for enhanced electrochemical nitrofurantoin detection: Implications in pharmaceutical pollutant monitoring

Synergistic integration of few-layer thick MXenes and small Pd nanocubes for enhanced electrochemical nitrofurantoin detection: Implications in pharmaceutical pollutant monitoring

High dispersion Pd nanoclusters modified sulfur-rich vacancies ZnIn2S4 for high-performance hydrogen evolution

High dispersion Pd nanoclusters modified sulfur-rich vacancies ZnIn2S4 for high-performance hydrogen evolution

Nearly monodisperse Cu|pd alloyed Nanocrystals: Ultrasound induced stepwise thermoreduction in organic Medium, and catalytic alcoholysis for hydrogen evolution

Nearly monodisperse Cu|pd alloyed Nanocrystals: Ultrasound induced stepwise thermoreduction in organic Medium, and catalytic alcoholysis for hydrogen evolution

Zn2+-responsive palladium nanoclusters synergistically manage Alzheimer’s disease through neuroprotection and inhibition of oxidative stress

Zn2+-responsive palladium nanoclusters synergistically manage Alzheimer’s disease through neuroprotection and inhibition of oxidative stress

Controllable Deposition of Bi onto Pd for Selective Hydrogenation of Acetylene.

The rational regulation of catalyst active sites at atomic scale is a key approach to unveil the relationship between structure and catalytic performance. Herein, we reported a strategy for the controllable deposition of Bi on Pd nanocubes (Pd NCs) in the priority order from corners to edges and then to facets (Pd NCs@Bi). The spherical aberration-corrected scanning transmission electron microscopy (ac-STEM) results indicated that Bi2O3 with an amorphous structure covers the specific sites of Pd NCs. When only the corners and edges of the Pd NCs were covered, the supported Pd NCs@Bi catalyst exhibited an optimal trade-off between high conversion and selectivity in the hydrogenation of acetylene to ethylene under ethylene-rich conditions (99.7% C2H2 conversion and 94.3% C2H4 selectivity at 170 °C) with remarkable long-term stability. According to the H2-TPR and C2H4-TPD measurements, the moderate hydrogen dissociation and the weak ethylene adsorption are responsible for this excellent catalytic performance. Following these results, the selectively Bi-deposited Pd nanoparticle catalysts showed incredible acetylene hydrogenation performance, which provides a feasible perspective to design and develop highly selective hydrogenation catalysts for industrial applications.

Ratiometric Electrochemiluminescence Sensing of Carcinoembryonic Antigen Based on Luminol.

Ratiometric electrochemiluminescence (ECL) sensors can efficiently remove environmental interference to attain precise detection. Nonetheless, two eligible luminophores or coreactants were usually needed, increasing the complexity and restricting their practical application. In this study, a single luminophore of luminol with a single coreactant of H2O2 was employed to construct a dual-potential ratiometric ECL sensor for the detection of carcinoembryonic antigen (CEA). The produced palladium nanoclusters (Pd NCs) employing a DNA duplex as a template could not only stimulate luminol to produce cathodic ECL (Icathodic) but also quench its anodic ECL (Ianodic). During the detection process, CEA could damage the double-stranded structure and reduce the Pd NCs' amount, triggering a significant decrease in the ratio of Icathodic to Ianodic (Icathodic/Ianodic) and thereby achieving sensitive CEA's detection. Furthermore, the Icathodic/Ianodic was independent of the H2O2 concentration, which avoided a prejudicial effect from H2O2 decomposition and considerably enhanced the detection's reliability. The developed ratiometric ECL sensor demonstrated a sensitive detection toward CEA with a wide linear range from 100 ag/mL to 10 ng/mL and a detection limit of 87.1 ag/mL (S/N = 3). In conclusion, this study offers a new idea for constructing ratiometric ECL sensors based on a single luminophore and technical support for cancer's early diagnosis.

Tuning structures of Pt shells on Pd nanocubes as neutral glucose oxidation catalysts and sensors

Tuning structures of Pt shells on Pd nanocubes as neutral glucose oxidation catalysts and sensors

Palladium nanocrystals-embedded covalent organic framework as an efficient catalyst for Heck cross-coupling reaction

Palladium nanocrystals-embedded covalent organic framework as an efficient catalyst for Heck cross-coupling reaction

Hierarchical-Structured Pd Nanoclusters Catalysts x-PdNCs/CoAl(O)/rGO-T by the Captopril-Capped Pd Cluster Precursor Method for the Highly Efficient 4-Nitrophenol Reduction.

Water-soluble captopril-capped atomically precise Pd nanoclusters (Pd17Capt8 NCs: 1.3 ± 0.5 nm) produced by a simple chemical reduction were supported on preprepared hybrid Co3Al-layered double hydroxide/reduced graphene oxide (Co3Al-LDH/rGO) by a pH-adjusted electrostatic adsorption strategy followed by proper calcinations, giving a series of novel catalysts x-PdNCs/CoAl(O)/rGO-T (x (Pd loading) = 0.09, 0.17, 0.43 wt % (ICP), T = 230, 250, 280, 300, 320 °C). The characterization results show that the as-obtained catalysts possess the hierarchical nanosheet array morphology. Pd NCs with a size of ∼1.3 to 1.8 nm are highly distributed at the edge sites of the CoAl(O) nanosheets. All of the x-PdNCs/CoAl(O)/rGO-T catalysts show superior catalytic efficiency for the conversion of 4-nitrophenol to 4-aminophenol, particularly 0.17-PdNCs/CoAl(O)/rGO-300 possesses the highest performance with a turnover frequency (TOF) of 30 042 h-1, which is the highest among the reported Pd-based catalysts so far. The superior activity of 0.17-PdNCs/CoAl(O)/rGO-300 can be owing to ultrafine Pd NCs with a clean surface, the strongest PdNCs-Co2+-OH(LDH)-rGO three-phase synergy, and the much improved adsorption of the substrate via π-π stacking upon nanosheet array morphology. Meanwhile, 0.17-PdNCs/CoAl(O)/rGO-300 exhibits excellent catalytic activities for various nitroarenes and anionic azo dyes as well as good reusability with the complete reduction of 4-nitrophenol (4-NP) within 90 s after 10 successive runs. The present work provides not only a simple and convenient strategy for the synthesis of clean, efficient, and environmentally friendly supported metal nanocluster catalysts but also a new idea for the efficient catalytic degradation of environmental pollutants.

Folic acid conjugated chitosan encapsulated palladium nanoclusters for NIR triggered photothermal breast cancer treatment

Folic acid conjugated chitosan encapsulated palladium nanoclusters for NIR triggered photothermal breast cancer treatment

Graphene nanosheets supported high-defective Pd nanocrystals as an efficient electrocatalyst for hydrogen evolution reaction

Graphene nanosheets supported high-defective Pd nanocrystals as an efficient electrocatalyst for hydrogen evolution reaction

A Sandwich-Type Electrochemical Immunosensor based on Pd Nanocubes Functionalized MoO2 Nanospheres for Highly Sensitive Detection of CEA

In this study, a sandwich-type electrochemical immunosensor was developed for detecting carcinoembryonic antigen (CEA) effectively. The proposed electrochemical immunosensor was based on gold nanocrystals (Au NDs) as the substrate material for capturing primary antibodies and using palladium nanoscale cubics (Pd NCs) loaded on amino-functionalized MoO2 nanospheres (Pd NCs/NH2-MoO2 NSs) as a secondary antibody label. Au NDs had dendritic structures that were more conducive to capturing Ab1 and can accelerate electron transfer. MoO2 had the good catalytic capacity for reduction of H2O2 and favourable electrical conductivity. Similarly, Pd NCs had excellent catalytic performance for hydrogen peroxide reduction. Hence, the obtained Pd NCs/NH2-MoO2 NSs were more effective than Pd NCs and NH2-MoO2 NSs in catalytic reduction of hydrogen attribute to a synergistic effect, showing excellent catalysis. The proposed electrochemical immunosensor had a lower detection limit of 3.3 fg ml−1 jand a wider detection range from 10 fg ml−1 to 100 ng ml−1 (S/N = 3) for the detection of CEA under optimal experimental conditions. The proposed electrochemical immunosensor showed good sensitivity, stability, selectivity, reproducibility and its good detection performance of the immunosensor indicated that it had a broad application prospect in clinical detection.