Jian Huang,Zhe Lei,Qian Zhang,Mei Juan Su,Liang Liu
Highly active Al-based Ag dendrites SERS plasmonic substrates have been rapidly synthesized by the one-step galvanic displacement reaction without the use of any surfactants and templates. The as-prepared SERS substrates were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy. XRD measurements confirmed the metallic nature of the formed Ag dendrites. None of the organic additives were used in the synthesis process, which ensures the substrates surfaces are completely clean and avoiding the introduction of organic contaminants. The innovative rough bionic substrates yield a final silver dendritic structure that offers large specific surface area and high-density hotspots. Using malachite green as a model target, the Al-based Ag dendrites SERS substrates exhibited acceptable reproducibility (relative standard deviation of 23.8%) and high enhancement capacities (pushed the detection limit down to 10 pM). Importantly, these Ag dendrites could potentially be employed as highly active and cost effective flexible SERS sensors for label-free ultrasensitive detection of biomolecules.
A surface-enhanced Raman spectroscopy (SERS)-active extraction column based on propanethiol modified silver dendrites was fabricated. The column, which combines the advantages of solid phase extraction and SERS, may facilitate the development of rapid analysis with high reliability and accuracy. High temporal stability (under a continuous and intensive laser radiation) and excellent repeatability (repeated extraction and elution) were also achieved using this column. As an example, the quantitative analysis of fluoranthene was accomplished in the concentration range of 0.01–100 μg mL−1 with this column. The extraction process could be accomplished in 10 s and the total time of one sample analysis including extraction, spectral acquisition, elution and intermediate process could be less than 30 s. This method can greatly simplify the sample preparation and reduce the total analysis time.
Designing economical and efficient nanocatalysts to enhance the efficiency and commercialization potential of direct ethanol fuel cells (DEFCs) is a challenging task. In the present study, we have crafted PdAg spatial nanodendrites (NDs) featuring distinct morphologies and precise compositional control, employing a streamlined one-step solvothermal approach. Modulating the molar quantity of the AgNO3 precursor can substantially modify the morphology and alloy composition of PdAg nanodendrites. The addition of Ag to the PdAg NDs resulted in lattice expansion, causing a shift in the d-band center of Pd. In addition, the porous nature of PdAg NDs provides numerous active sites for catalytic reactions, significantly enhancing the activity and stability of the ethanol oxidation reaction (EOR). It is important to note that the PdAg NDs exhibit “volcano” characteristics. Among these, the Pd9Ag1 NDs demonstrate excellent electrocatalytic activity and outstanding stability. It has been found to have an electrocatalytic activity of 2450 mA mgpd–1 for ethanol oxidation. This study offers a solution for the preparation of catalysts for fuel cells and motivates the creation of innovative structures to improve electrocatalytic activities.
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