An environmentally-friendly method for the synthesis of Au-Ag alloy nanoparticles with controlled composition is proposed. The method involves the simultaneous bioreduction of HAuCl 4 and AgNO 3 using Cacumen Platycladi leaf extract at 90 uC. The formation of the Au-Ag alloy nanoparticles was monitored by recording the absorbance, using UV-visible light spectroscopy as a function of the reaction time and the formation process. The as-synthesized nanoparticles were characterized by X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy to verify the nature of the alloy. The Fourier transform infrared spectra show that the CLC, N-H, (NH) CLO, and -OH groups in the C. Platycladi extract served as a reducing agent, whereas the peptides or proteins prevented the aggregation of alloy nanoparticles. The process can be described as a purely ''green technique'' because no additional synthetic reagents were used as reductants or stabilizers.

40 nm flower-shaped Au-Pd bimetallic nanoparticles were prepared in a facile and eco-friendly way based on the simultaneous bioreduction of HAuCl 4 and Na 2 PdCl 4 with ascorbic acid and CacumenPlatycladi leaf extract at room temperature. Characterization techniques, such as transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction, were employed to confirm that the as-synthesized nanoparticles were alloys. The obtained flower-shaped Au-Pd alloy nanoparticles exhibited an excellent surface enhanced Raman spectroscopic activity with rhodamine 6G and efficient catalytic ability for the oxidation of benzyl alcohol to benzaldehyde.

In this paper, we present a simple and facile strategy to prepare highly uniform Pd-Pt alloy nanoparticles (NPs) with different Pt/Pd molar ratios on 1-pyrenecarboxylic acid (PCA) decorated graphite nanoplatelets (GNPs). The binary composition of these Pd-Pt/GNPs catalysts is controlled by simply adjusting the molar ratio of the Pd and Pt precursors. The obtained catalysts were characterized by ultraviolet-visible light (UV-vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma optical emission spectrometry (ICP-OES). The HRTEM measurements show that all of the metallic NPs exhibit well-defined crystalline structures. Both cyclic voltammetry (CV) and chronoamperometry (CA) demonstrate that the Pd 1 Pt 3 /GNPs catalyst has the highest catalytic activity towards methanol oxidation reaction (MOR) among the Pd-Pt/GNPs with different compositions studied. Moreover, the Pd 1 Pt 3 /GNPs catalyst markedly outperforms Pt/GNPs and the commercial Pt/C-JM catalyst in terms of both MOR activity and stability. The present method represents a simple and general approach to synthesizing bimetallic Pt-M electrocatalysts on an alternative carbon support, which is expected to find applications in fuel cells.

In the search for alternatives to conventional Pt electrocatalysts, we synthesized a series of graphene nanoplate (GNP)-supported Pt3Cu1 nanocrystals (NCs), possessing almost the same composition but different morphologies to probe their electrochemical properties as a function of morphology for the ethanol oxidation reaction. The morphology of the Pt3Cu1 catalysts could be systematically evolved from dendritic (D-Pt3Cu1/GNPs) to wire-like (W-Pt3Cu1/GNPs) and spherical (Pt3Cu1/GNPs) by only varying pH of the reaction solution. The as-prepared Pt3Cu1 catalysts were subsequently characterized using a suite of techniques including transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), inductively coupled plasma mass spectrometry (ICP-MS) and X-ray photoelectron spectroscopy (XPS) to verify not only their morphologies and chemical compositions but also the incorporation of Cu into the Pt lattice, as well as physical structure and integrity. Gratifyingly, the three Pt3Cu1 catalysts exhibited superior electrocatalytic properties for the ethanol oxidation compared to the monometallic Pt/GNPs and Pt/C-JM (Johnson Matthey), with the activities, durabilities and anti-poisonous abilities following the order Pt3Cu1/GNPs < W-Pt3Cu1/GNPs < D-Pt3Cu1/GNPs.