Theranostic nanoparticles that possess multiple diagnostic modalities and allow spatiotemporally controlled therapies can significantly improve therapeutic outcomes and reduce adverse effects. Here, ...an intelligent and biocompatible theranostic formulation is developed based on dendritic platinum–copper alloy nanoparticles (DPCN) for cancer therapy. DPCN have excellent photothermal effect, and can load anticancer drugs such as doxorubicin in their porous structure and release the loaded drugs in response to near infrared light or moderate acidic stimulus. They also inherently have multimodal imaging modalities. Upon the guidance of photoacoustic imaging, DPCN‐mediated photothermal treatment efficiently inhibits tumor growth in vivo. Furthermore, doxorubicin‐loaded DPCN completely suppress the tumor growth even under a low treatment temperature, which avoids hypothermia‐induced damage to normal tissues. Our study develops an excellent theranostic nanoparticle with inherent multimodal imaging and therapeutic modalities for chemophotothermal cancer therapy.
Dendritic platinum–copper alloy nanoparticles (DPCN) are developed as an excellent theranostic agent. DPCN inherently possess multimodal imaging modalities, photothermal effect, and drug loading capability. Upon the guidance of photoacoustic imaging, DPCN‐mediated chemophotothermal treatment efficiently inhibits the tumor growth in vivo.
Research on the cathode catalysts of lithium–oxygen (Li–O2) batteries is one of the most important branches to commercialize these batteries to overcome the sluggish kinetics during both the oxygen ...reduction reaction (ORR) and the oxygen evolution reaction (OER). In this study, a high performance catalyst based on a bimetallic Pt–Cu alloy is investigated for Li–O2 batteries using first-principles calculation. The theoretical prediction shows that the Pt–Cu alloy is much more effective than the pure Pt according to the electrochemical performance. In particular, the effectiveness of the catalytic property is maximized in the case of the PtCu (111) surface which greatly reduces the large overpotentials of the original Li–O2 batteries during the OER/ORR. It is identified for the first time that the charge overpotentials are affected mainly by the inherent surface charge character of the alloy catalyst. It is observed that the more negatively charged PtCu (111) surface can act as a weakly positively charged surface for the adsorption of Li–O intermediates and thus result in weak ionic bonding of the intermediates on the surface. As a result, the dominant factor improving the catalytic performance is clearly demonstrated, providing insight into the design of an efficient catalyst for Li–O2 battery technologies.
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•Li–O2 reactions are investigated on Pt–Cu alloy catalysts using DFT calculation.•PtCu (111) has greatly reduced overpotentials, ηC = 0.49 V and ηDC = 0.26 V.•Inherent surface charge of alloy catalyst mainly affects η of Li–O2 battery.•Pt-based alloys have general rule for Li–O2 reactions decided by surface charge.
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In this work, the PtCu electrocatalyst supported on graphdiyne (PtCu/GDY) nanocomposite was synthesized for methanol oxidation reaction (MOR). The results demonstrated that the ...obtained PtCu/GDY catalyst has a good dispersion on graphdiyne. The electrochemical experiments indicated that the PtCu/GDY displayed a superior electrocatalytic activity towards MOR with a high mass activity of 336 mA mg−1. Furthermore, the presence of GDY can significantly improve the CO tolerance property of PtCu for MOR, which facilitating OHads generation from H2O decomposition. Therefore, the PtCu/GDY electrocatalyst offers an exciting opportunity to be commercialization of direct methanol fuel cells.
Electrocatalysts based on Pt-M bimetallic nanoparticles deposited on carbon supports have already been used in commercially available Proton Exchanged Membrane Fuel Cells (PEM FC). Nevertheless, ...production and practical use of such materials faces with the problems caused by the need to combine high specific activity in current-forming reactions and their durability, with the stability of the element's composition during the operation of PEM FC. The suggested stepwise approach to the PtCu/C materials synthesis in the liquid phase is based on the initial deposition of platinum nuclei and their subsequent growth due to the joint or sequential deposition of copper and platinum from the solutions of their precursors. The PtCu/C catalysts, obtained in this way, demonstrated not only higher activity in oxygen reduction reaction compared to the commercial Pt/C catalyst, but also a significantly higher corrosion-morphological stability.
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•A new step-by-step approach to the synthesis of improved Pt(Cu)/C catalysts.•Ultra-small Pt NPs are used as nuclei in the formation of PtCu NPs.•ORR activity of Pt(Cu)/C is significantly higher than that of commercial Pt/C.•Bimetallic nanoparticles of uneven structure retain copper even after stress test.
The controllable synthesis of noble metal alloy nanostructures with highly branched morphology has attracted much attention because of their specific physical and chemical properties. This article ...reports the synthesis of platinum–copper bimetallic alloy nanodendrites (Pt–Cu BANDs) by a facile, one-pot, templateless, and seedless hydrothermal method in the presence of poly(allylamine hydrochloride) (PAH) and formaldehyde (HCHO). The morphology, composition, and structure of Pt–Cu BANDs are fully characterized by various physical techniques, demonstrating Pt–Cu BANDs are highly alloying, porous, and self-supported nanostructures. The formation/growth mechanism of Pt–Cu BANDs is explored and discussed based on the experimental observations. The autocatalytic growth and interdiffusion are responsible for the formation of Pt–Cu alloy whereas selective oxidative etching results in dendritic morphology of Pt–Cu alloy nanostructures. In addition, the electrocatalytic activity and stability of Pt–Cu BANDs for the methanol oxidation reaction (MOR) are investigated by various electrochemical techniques. The synthesized Pt–Cu BANDs show higher electrocatalytic activity and stability than commercially available Pt black.
Pt-based core–shell electrocatalysts with one-dimensional (1D) nanostructure show a great opportunity to improve the catalytic activity and durability of pure Pt catalyst for oxygen reduction ...reaction (ORR). Here, we synthesize Cu@CuPt core@shell nanowires (NWs) with 1D nanostructure by using Cu NWs as templates in organic solvent medium. The ORR mass activity and specific activity of PtCu NWs are 0.216 A mgpt−1 and 0.404 mA cm−2 at 0.9 V, respectively, which are 3.1 and 3.7 times larger than that of the commercial Pt/C catalyst (0.07 A mgpt−1 and 0.110 mA cm−2, respectively). Theoretical studies suggest that the electronic effect of the Cu substrate on the Pt monolayer could be the main reason for the higher activity of PtCu NWs than that of the commercial Pt/C catalyst. In addition, the PtCu NWs show much better durability than the commercial Pt/C catalyst after stability test. It is expected that the as-synthesized PtCu NWs in organic solvent medium could be excellent candidates as high performance catalysts for ORR.
•Cu@CuPt core@shell nanowires were synthesized in organic solvent medium.•PtCu nanowires exhibit superior catalytic activity toward the oxygen reduction reaction.•PtCu nanowires show much better durability than the commercial Pt/C catalyst.•Theoretical studies are used to understand the mechanism of enhanced ORR activity.
The lattice structure is known to influence interfacial reactivities of nanoscale alloy catalysts, but little is known about how the lattice strain can be sustainably controlled by the nanoscale ...morphology under electrocatalytic reaction conditions. Herein, a previously unknown self-regulated stability of lattice strains is demonstrated by engineering highly active platinum–copper alloy nanowires with two distinctive types of morphology. The dendritic alloy nanowires exhibit the best performance for oxygen reduction reaction among the reported platinum–copper alloy catalysts. In comparison with the initial difference of compressive lattice strains between smooth and dendritic nanowires, the strains are shown to be controllable, which coincides with the highly durable electrocatalytic performance throughout the duration of oxygen reduction reaction despite the occurrence of dealloying. By thorough characterizations of the nanowire morphologies, compositions, and lattice strains, the self-regulated stability of lattice strains is revealed to originate from the operation of a combination of morphology-tuned compressive strain and realloying in the dendritic nanowires for the enhanced electrocatalytic activity and durability. These findings have significant implications for the design of high-durability alloy catalysts in heterogeneous catalysis.
Designing highly efficient and durable electrode for methanol oxidation reaction (MOR) is crucial to commercializing direct methanol fuel cells (DMFCs). However, traditional Pt/C catalysts usually ...suffer from CO poisoning, and agglomeration of powder catalyst, which leads to rapid activity degradation. Herein, we have successfully fabricated self-supported Pt3Cu@3DP-WO3/W electrode via a facile and effective synthesis approach by combining anodic oxidation and electrodeposition method. Benefitting from the three dimensional nanoporous of WO3 with more surface area and strong adhesion, and Pt3Cu alloy synergism induced the lattice compressive strain, the Pt3Cu@3DP-WO3/W electrode achieved 2.77-fold and 4.8-fold enhancement in specific activity (2.15 mA cm−2) and mass activity (853 mA·mgPt−1) for MOR relative to Pt/C catalysts, respectively. Moreover, both the experiments and theoretical calculations revealed that the doping of Cu element weakened the chemisorption of CO-like intermediates by lowering the Pt d-band center through compressive lattice strain, which resulting in excellent catalytic stability. This binder-free self-supported electrode is a viable alternative for commercial application of DMFCs.
•3D porous structure of WO3 provided more specific surface area and strong adhesion.•Pt3Cu alloy with more loose and porous obtained by the electrochemical co-deposition.•The doping of Cu reduced the Pt d-band center through compressive lattice strain.•Pt3Cu@3DP-WO3/W electrode had 4.8 times enhanced in mass activity to commercial Pt/C.
On page 5971, Q. Zhang, Y. Cheng, and co‐workers describe a dendritic platinum‐copper alloy nanoparticle (DPCN) inherently possessing multimodal image modalities, photothermal effect, drug loading ...capability, and responsive release behaviors. Efficient tumor ablation in DPCN‐mediated chemo‐photothermal therapy proves the potential of this approach for cancer therapy.
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