One-Pot Fabrication of Mesoporous Core-Shell Au@PtNi Ternary Metallic Nanoparticles and Their Enhanced Efficiency for Oxygen Reduction Reaction

Multi-omics analysis of Au@Pt nanozyme for the modulation of glucose and lipid metabolism

Au@Pt nanozyme, a bimetallic core-shell structure Au and Pt nanoparticle, has attracted significant attention due to its excellent catalytic activity and stability. Here, we propose that Au@Pt improves glucose tolerance and reduces TG after four weeks administration. The transcriptomic analysis of mouse liver tissues treated with Au@Pt nanozyme showed changes in genes related to glucose and lipid metabolism signaling pathways, including glycolysis/gluconeogenesis, pyruvate metabolism, PPAR signaling, and insulin signaling. Moreover, analysis of fecal samples from mice treated with Au@Pt nanozyme showed significant changes in the abundance of beneficial gut microbiota such as Dubosiella, Parvibacter, Enterorhabdus, Monoglobus, Lachnospiraceae_UCG-008, Lachnospiraceae_UCG-006, Lachnospiraceae_UCG-001, and Christensenellaceae_R-7_group. Combined multi-omics correlation analyses revealed that the modulation of glucose and lipid metabolism by Au@Pt was strongly correlated with changes in hepatic gene expression profiles as well as changes in gut microbial profiles. Overall, our integrated multi-omics analysis demonstrated that Au@Pt nanozyme could modulate glucose and lipid metabolism by regulating the expression of key genes in the liver and altering the composition of gut microbiota, providing new insights into the potential applications of Au@Pt nanozyme in the treatment of metabolic disorder.

Trimetallic Au@Pd@Pt nanozyme-enhanced lateral flow immunoassay for the detection of SARS-CoV-2 nucleocapsid protein

The rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seriously threatened global public health. Establishing a rapid and sensitive diagnostic test for early detection of the SARS-CoV-2 nucleocapsid protein is urgently required to defend against the pandemic. Herein, an enhanced lateral flow immunoassay (LFIA) was fabricated by trimetallic Au@Pd@Pt core-shell nanozymes for detection of the SARS-CoV-2 nucleocapsid protein. The Au@Pd@Pt nanozymes (Au@Pd@Pt NZs) synthesized via a one-pot method, with a dendrite morphology and uniform particle size, showed excellent peroxidase-like activity. Due to the perfect enzyme-like catalytic activity toward 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H₂O₂), the catalytic signal could be generated even by a tiny amount of Au@Pd@Pt NZs accumulated on the test strip. Therefore, rapid detection with higher sensitivity was achieved. The Au@Pd@Pt NZs-based LFIA provided a quantitative range of 0.05-100 ng mL^-1 with a limit of detection of 0.037 ng mL^-1, which was 17-fold lower than the LFIA without enhancement. The average recoveries from spiked samples were in the range of 92.5-107.9% with relative standard deviations all less than 4%, indicating the reliability and repeatability of the proposed LFIA. Additionally, the proposed LFIA could report results within 30 min using a microplate reader. In conclusion, the Au@Pd@Pt NZs-LFIA is a rapid, simple, and sensitive method for detecting the SARS-CoV-2 nucleocapsid protein.

Spectroscopic Verification of Adsorbed Hydroxy Intermediates in the Bifunctional Mechanism of the Hydrogen Oxidation Reaction

Elucidating hydrogen oxidation reaction (HOR) mechanisms in alkaline conditions is vital for understanding and improving the efficiency of anion-exchange-membrane fuel cells. However, uncertainty remains around the alkaline HOR mechanism owing to a lack of direct in situ evidence of intermediates. In this study, in situ electrochemical surface-enhanced Raman spectroscopy (SERS) and DFT were used to study HOR processes on PtNi alloy and Pt surfaces, respectively. Spectroscopic evidence indicates that adsorbed hydroxy species (OH_ad ) were directly involved in HOR processes in alkaline conditions on the PtNi alloy surface. However, OH_ad species were not observed on the Pt surface during the HOR. We show that Ni doping promoted hydroxy adsorption on the platinum-alloy catalytic surface, improving the HOR activity. DFT calculations also suggest that the free energy was decreased by hydroxy adsorption. Consequently, tuning OH adsorption by designing bifunctional catalysts is an efficient method for promoting HOR activity.

Atomically dispersed metal–nitrogen–carbon catalysts for fuel cells: advances in catalyst design, electrode performance, and durability improvement

The review provides a comprehensive understanding of the atomically dispersed metal–nitrogen–carbon cathode catalysts for proton-exchange membrane fuel cell applications.

Core@shell nanostructured Au-d@NimPtm for electrochemical oxygen reduction reaction: effect of the core size and shell thickness

Au-d@Ni_mPt_m nanostructures are studied to address the effects of the Au-core size (d) and NiPt-shell thickness (m) on the electrocatalytic performance of Pt for the ORR.

One-step fabrication of bimetallic PtNi mesoporous nanospheres as an efficient catalyst for the oxygen reduction reaction

The controlled synthesis of Pt-based bimetallic porous nanostructures is highly important for the design of electrocatalysts with high performance. Herein, we report a one-step method for the direct synthesis of well-dispersed bimetallic PtNi mesoporous nanospheres (PtNi MNs) at high yield. Benefitting from the synergistic effect of composition (bimetallic PtNi) and structure (mesoporous and highly open structure), the as-obtained PtNi MNs exhibit superior catalytic activity and stability for the oxygen reduction reaction.

Facile construction of fascinating trimetallic PdAuAg nanocages with exceptional ethylene glycol and glycerol oxidation activity

Highly open metallic nanocages represent a novel class of nanostructures for advanced catalytic applications in direct liquid fuels cells due to their specific capability of providing easy access to reactants in both internal and external active sites and also desirable electronic structures for the adsorption of molecules, which render superior catalytic performances. However, to date, the rational design of trimetallic nanocages with tunable compositions remains a challenge. Herein, we demonstrate a facile method combining seed mediated and galvanic replacement for the preparation of unique trimetallic Pd-Au-Ag nanocages catalysts with tunable compositions. A series of controlled experiments reveal that the reaction time plays a crucial role in affecting the morphology of the final product. Importantly, the newly-generated Pd-Au-Ag nanocages are high-performance electrocatalysts for the oxidation of both ethylene glycol and glycerol with mass activities of 7578.2 and 5676.1 mA mg^-1, respectively, which are far superior to that of commercial Pd/C. We firmly believe that the strategy and enhanced electrocatalysts developed in this study can be well applied to boost the commercial development of fuel cell technologies.

Mitochondrial-targeted multifunctional mesoporous Au@Pt nanoparticles for dual-mode photodynamic and photothermal therapy of cancers

In the conventional non-invasive cancer treatments, such as photodynamic therapy (PDT) and photothermal therapy (PTT), light irradiation is precisely focused on tumors to induce apoptosis via the generation of reactive oxygen species (ROS) or localized heating. However, overconsumption of oxygen and restricted diffusion distance of ROS limit the therapeutic effects on hypoxic tumors. Herein, we developed a platform for the rapid uptake of multifunctionalized Au@Pt nanoparticles (NPs) by mitochondria in cancer cells. The mesoporous Au@Pt nanoparticles were labeled with a cell-targeting ligand (folic acid), a mitochondria-targeting group (triphenylphosphine (TPP)), and a photosensitizer (Ce6). This led to significant improvement of the PDT efficacy due to an enhanced cellular uptake, an effective mitochondrial ROS burst, and a rapid intelligent release of oxygen. Moreover, Au@Pt NPs can convert laser radiation into heat, resulting in thermally induced cell damage. This nanosystem could be used as a dual-mode phototherapeutic agent for enhanced cancer therapy and molecular targets associated with disease progression. We achieved a mitochondria-targeted multifunctional therapy strategy (a combination of PDT and PTT) to substantially improve the therapeutic efficiency.

Hollow AuxAg/Au core/shell nanospheres as efficient catalysts for electrooxidation of liquid fuels

One plausible approach to endow nanocrystals with both enhanced catalytic activity and stability for the electrooxidation of liquid fuels is to chemically control the crystal structures of nanoparticles. To date, core-shell and alloy structures have been demonstrated to offer generally two precious opportunities to design highly efficient nanocatalysts for the electrooxidation reaction of organic molecules. We herein combine these two advantages and develop a general method to successfully synthesize hollow Au_xAg/Au core/shell nanospheres with a high yield approaching 100% via a combined seed mediated and galvanic replacement method. The results from the electrochemical measurements have revealed that this as-obtained hollow Au_xAg/Au core/shell nanosphere exhibited considerably high electrocatalytic performance towards ethylene glycol and glycerol oxidation with mass activity of 4585 and 3486 mA mg_Au^-1, which were 5.3- and 5.8-fold higher than that of pure Au. We trust this strategy may be extended to the syntheses of other multimetallic nanocatalysts with such fascinating nanostructures and the as-obtained hollow Au_xAg/Au core/shell nanospheres can be well applied to serve as highly desirable anode catalysts for the electrooxidation of ethylene glycol and glycerol.

Facile synthesis and heteroepitaxial growth mechanism of Au@Cu core–shell bimetallic nanocubes probed by first-principles studies

This work provided a facile strategy for the synthesis of Au@Cu core–shell nanostructures. The proposed growth mechanism was probed by a first-principles investigation.

Facile synthesis of hollow dendritic Ag/Pt alloy nanoparticles for enhanced methanol oxidation efficiency

Hollow dendritic Ag/Pt alloy nanoparticles were synthesized by a double template method.

Effective new method for synthesizing Pt and CoPt3 mesoporous nanorods. New catalysts for ethanol electro-oxidation in alkaline medium

An electrochemical methodology consisting of electrodeposition in IL/W microemulsions has been revealed as an excellent pathway to prepare highly mesoporous nanorods with pore sizes of a few nanometers, with a significant growth rate.