Search

Direct formic acid fuel cells have attracted significant attention due to their low fuel crossover, high safety, and high theoretical power density among all proton‐exchange membrane fuel cells. Numerous efforts have been dedicated to studying formic acid oxidation, particularly in the fabrication of high‐performance electrocatalysts with economical utilization of Pt metal. In this work, we report a synthetic strategy to create PtAg dots supported on plate‐like Au nanoparticles and explore their applications in electrocatalytic formic acid oxidation. The highly dispersed nature of the catalytic Pt centers and the successful construction of PtAg−Au trimetallic interfaces makes the current nanostructure an ideal system to allow for a synergetic effect between Pt, Au, and Ag, leading to improved electrocatalysis. Compared with commercial Pt/C, our PtAg‐on‐Au heterogenous nanoplates exhibit superior mass activity, along with enhanced reaction kinetics and long‐term durability for FAOR in an acidic medium. Density functional theory (DFT) simulation results indicate that AgPtAu(111) exhibits a relatively high activity for HCOOH oxidation into CO2 among the various Au‐based catalysts. This work provides a viable strategy for constructing Pt‐based electrocatalysts with controlled Pt ensembles, offering insights into the development of fuel cell catalysts that make highly efficient use of costly noble metals. [ABSTRACT FROM AUTHOR]

Ultrathin two-dimensional (2D) nanostructures, with superhigh exposure of the under-coordinated metal atoms relative to large-sized quasi-spherical particles or bulk counterparts, have shown enormous potential to enhance various heterogeneous catalytic reactions. The creation of in-plane holes and rational assembling of ultrathin 2D nanosheets into 3D hierarchical architectures can prevent the restacking issue of nanosheets, thereby providing more active sites by hampering atomic diffusion, nearby nanosheet aggregation, and thermodynamic structural reform. Herein, we report the stepwise construction of ultrathin CuAuAg nanosheet-assembled 3D nanoflowers (NFs). The synthesis involves the conversion of Au@CuxO mesoporous nanospheres into CuAg NFs, followed by a controlled galvanic replacement reaction with chloroauric acid to create holes and manipulate the atomic ratio between Cu, Au, and Ag. With strong broad-spectrum light absorption across the UV–vis region, the current CuAuAg NFs exhibited satisfactory photothermal conversion under Xe lamp irradiation. When serving as HER electrocatalysts, the Cu10.5Au58.4Ag31.1 NFs displayed the optimized performance in terms of overpotential and activity, surpassing the Cu71.4Ag28.6 NFs and Au NCs, which is supported by DFT simulations, showcasing the multimetallic coupling advantage for HER. This study presents a viable route to construct trimetallic 3D hierarchical nanostructures and validates their application in photothermal conversion and electrocatalytic HER, guiding the design of high-performance photosensitizers and electrocatalysts. [ABSTRACT FROM AUTHOR]

Porous ceramic silicone rubber (PCSR) has an excellent ablative resistance because of its strong carbon layer structure after burning. However, as a marine sealant material, it also needs to have better mechanical properties for better application. In this study, PCSR composites were prepared by compounding with different additives and different viscosity base adhesives, and their fire resistance, tensile properties, and bond strength of multiple substrates at different temperatures were investigated and compared. When the ratio of 20,000 to 80,000 viscosity matrix adhesive is 3:7, the material prepared by adding deketoxime crosslinker and silane coupling agent containing amino and epoxy groups together can reach more than 1.4 MPa tensile shear strength at 150°C. Sintering experiments have shown that PCSR composites can still maintain the strength and integrity of the carbon layer structure, and the results of the A‐60 standard fire resistance test for cable and pipe penetration devices have shown that marine PCSR sealants can effectively prevent flame propagation. [ABSTRACT FROM AUTHOR]

Rational assembling of different noble metal nanocrystals with controlled nanogaps in one entity allows the efficient coupling of electromagnetic fields of each component and versatile manipulation over the overall physiochemical properties. In the present study, we report a stepwise synthetic strategy to hybridlike assemble Au nanoplate and Ag nanoparticles without direct physical contact. Particularly, the success of current work relies on the conformal coating of Cu2O over the Au nanoplate as an intermediate layer, followed by the in situ formation of Ag nanoparticles via the galvanic replacement reaction between Cu2O and Ag+. With the anchoring of Ag nanoparticles over the Cu2O‐wrapped Au nanoplate, the resulting hybrid nanostructures exhibit noticeable multiple plasmonic absorptions across the UV‐vis‐NIR region. The potential use as the plasmonic catalyst for current Au@Cu2O‐Ag hybrid products is validated using reduction of 4‐nitrophenol as the model reaction, where the catalytic performance is greatly improved by the UV‐vis light irradiation. They also exhibit satisfactory photothermal conversion performance under the irradiation of Xe lamp. The current work provides a niche strategy to create noble‐metal hybrid nanostructures with controlled interparticle distance and tunable plasmonic properties, could be extended to other noble metal or alloys. [ABSTRACT FROM AUTHOR]

We report the preparation of plasmonic Janus nanostructures, composed of solid and hollow interiors, respectively, via a stepwise seeded growth. The success of the current synthesis highly relies on the construction of AuAg-based Janus nanocrystals with well-defined structures and the following controlled galvanic replacement reaction to prominently carve the Ag parts into hollow derivatives. With such unique architecture, they are enabled with the optical feature of dual plasmonic absorptions in the visible and near-infrared range and benefit the utilization of incident light and thus the photothermal conversion. The optimal temperature rise (ΔT) of the aqueous suspension was 15.2 °C after 10 min of 808 nm laser irradiation at a power density of 1.0 W cm–2, which was effective against multidrug-resistant bacteria in vitro. The current work shows a feasible synthetic strategy to create plasmonic Janus nanostructures featuring different porosities on each side, shedding light on rational design of advanced photothermal nanomaterials in biomedicine applications. [ABSTRACT FROM AUTHOR]

Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)