Heterogeneous Au-Pt nanostructures have been synthesized using a sacrificial template-based approach. Typically, monodispersed Au nanoparticles are prepared first, followed by Ag coating to form core-shell Au-Ag nanoparticles. Next, the galvanic replacement reaction between Ag shells and an aqueous H(2)PtCl(6) solution, whose chemical reaction can be described as 4Ag + PtCl(6)(2-)→ Pt + 4AgCl + 2Cl(-), is carried out at room temperature. Pure Ag shell is transformed into a shell made of Ag/Pt alloy by galvanic replacement. The AgCl formed simultaneously roughens the surface of alloy Ag-Pt shells, which can be manipulated to create a porous Pt surface for oxygen reduction reaction. Finally, Ag and AgCl are removed from core-shell Au-Ag/Pt nanoparticles using bis(p-sulfonatophenyl)phenylphosphane dihydrate dipotassium salt to produce heterogeneous Au-Pt nanostructures. The heterogeneous Au-Pt nanostructures have displayed superior catalytic activity towards oxygen reduction in direct methanol fuel cells because of the electronic coupling effect between the inner-placed Au core and the Pt shell.
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http://dx.doi.org/10.1039/c2dt11960a | DOI Listing |
ACS Nano
July 2024
Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States.
Metal oxides are widely used in heterogeneous catalysis as supports to disperse catalytically active nanoparticles, isolated atomic sites, or even as catalysts themselves. Herein, we present a method to produce optically active metal oxide supports that exhibit size-dependent Mie resonances based on TiO nanospheres with tunable size, crystalline phase composition, and optical properties. Mie resonant TiO nanospheres were used as supports to disperse Au, Pt, and Pd nanoparticles.
View Article and Find Full Text PDFCrit Rev Anal Chem
June 2024
Department of Chemistry and Nanoscience, Ewha Womans University, Seoul, Republic of Korea.
Electrochemical measurements involving single nanoparticles have attracted considerable research attention. In recent years, various studies have been conducted on single-entity electrochemistry (SEE) for the in-depth analyses of catalytic reactions. Although, several electrocatalysts have been developed for H energy production, designing innovative electrocatalysts for this purpose remains a challenging task.
View Article and Find Full Text PDFMikrochim Acta
April 2024
Department of Electrical and Electronics Engineering, METU, Ankara, Turkey.
The growing interest in microfluidic biosensors has led to improvements in the analytical performance of various sensing mechanisms. Although various sensors can be integrated with microfluidics, electrochemical ones have been most commonly employed due to their ease of miniaturization, integration ability, and low cost, making them an established point-of-care diagnostic method. This concept can be easily adapted to the detection of biomarkers specific to certain cancer types.
View Article and Find Full Text PDFChem Rec
November 2023
National Research Institute of Brewing (NRIB), Higashihiroshima, Hiroshima, 739-0046, Japan.
Heterogeneous noble metal catalysts exhibit various functions. Although their redox functions have been extensively studied, we focused on their soft Lewis acid functions. Supported Au, Pt, and Pd catalysts electrophilically attack the π-electrons of soft bases such as alkynes, alkenes, and aromatic compounds to perform addition and substitution reactions.
View Article and Find Full Text PDFBiosens Bioelectron
August 2023
Key Laboratory for Biobased Materials and Energy of Ministry of Education, College of Materials and Energy, South China Agricultural University, Guangzhou, 510642, China; The Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou, 510642, China. Electronic address:
The construction of an immunosensor based on ultralong chemiluminescence is challenged due to the shortage of highly efficient initiator for long and stable catalysis. Herein, the heterogeneous Au/Pt@CuO/CuO catalyst was used to investigate the structure-activity relationship, while Au/Pt significantly promotes the activity of CuO/CuO to catalyze HO and thus produces ·OH and O radicals in highly alkaline solutions, resulting in the strong and long chemiluminescence in the reaction with luminol (10 mL, more than 4 min with 1 μg catalyst). By using the Au/Pt@CuO/CuO as the label in the immunoassay, the strong and long chemiluminescence could initiate the photocurrent of the photoelectrochemical (PEC) substrate, and the luminescence time could influence the photocurrent extinction time, thus a self-powered time-resolved PEC immunosensor was developed to detect furosemide, showing a linear relationship between the extinction time and the logarithm of concentrations from 10 to 1 μg/L.
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