Ke-Ming Fang

One-step, seedless wet-chemical synthesis of gold@palladium nanoflowers supported on reduced graphene oxide with enhanced electrocatalytic properties

Herein, a simple, one-step seedless wet-chemical method was developed for synthesis of well-dispersed gold@palladium core–shell nanoflowers supported on reduced graphene oxide (Au@Pd/rGO) with the assistance of melamine as a linking agent and using poly(vinylpyrrolidone) as a structure-directing agent. The as-prepared Au@Pd/rGO exhibited enhanced electrocatalytic activity and improved stability for oxygen reduction reaction (ORR) and ethylene glycol (EG) oxidation in alkaline media compared with Pd/rGO, Au/rGO, and Pd black. This method can be extended to easily prepare core–shell nanostructures with designed compositions and desired catalytic properties.

Gelatin-assisted hydrothermal synthesis of single crystalline zinc oxide nanostars and their photocatalytic properties

Biotemplate-assisted approach is simple and friendly to the environment. With the assistance of gelatin as a soft biotemplate and a structure-directing agent, star-like zinc oxide (ZnO) nanostructures have been prepared by assembly of well-defined nanorods under hydrothermal conditions. Their morphology and structures were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The growth mechanism of the ZnO nanostars is also investigated. The as-prepared ZnO nanostars display high photocatalytic activity toward the degradation of methyl orange (MO) under ultraviolet (UV) irradiation.

Simple one-pot aqueous synthesis of AuPd alloy nanocrystals/reduced graphene oxide as highly efficient and stable electrocatalyst for oxygen reduction and hydrogen evolution reactions.

Herein, we develop a simple one-pot aqueous method to prepare AuPd alloy nanocrystals on reduced graphene oxide (AuPd NCs/rGO), by using 1-acetyl-4-(p-hydroxyphenyl) piperazine (AHPP) as the reductant, stabilizing agent and structure-director, without any other additives (e.g., seed, surfactant or polymer). The product is mainly characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction and thermogravimetric analysis. The obtained AuPd NCs/rGO displays enlarged electrochemically active surface area and superior catalytic performances toward oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) relative to Pt/C, Pd/C, Pd/rGO and Au/rGO catalysts, showing promising applications in energy storage and conversion.

One-pot synthesis of hollow AgPt alloyed nanocrystals with enhanced electrocatalytic activity for hydrogen evolution and oxygen reduction reactions

Herein, a simple one-pot aqueous method was developed for the fabrication of uniform hollow bimetallic AgPt alloyed nanocrystals (H-AgPt NCs) by using 5-aminoorotic acid (5-amino-2,6-dioxo-1,2,3,6-tetrahydropyrimidine-4-carboxylic acid) as a growth-directing agent, without any seed, organic solvent or template involved. The prepared H-AgPt NCs displayed enhanced electrocatalytic activity for hydrogen evolution reaction (HER) with a more positive onset overpotential (ηonset) of -28mV and a smaller Tafel slope of 40mVdec-1 relative to commercial Pt black (-34mV, 50mVdec-1) and Pt/C (20wt.%, -33mV, 33mVdec-1) in 0.5M H2SO4. Meanwhile, the obtained catalyst exhibited improved catalytic features toward oxygen reduction reaction (ORR) with a positive ηonset (0.916V) and enhanced kinetic current density (243.23mAmg-1Pt) in 0.1M HClO4 at 0.850V compared with Pt black (0.876V, 25.85mAmg-1Pt).

Facile synthesis of bimetallic gold-palladium nanocrystals as effective and durable advanced catalysts for improved electrocatalytic performances of ethylene glycol and glycerol oxidation.

In this work, well-defined bimetallic AuPd alloyed nanocrystals (AuPd NCs) were facilely synthesized by a straightforward and controllable one-step wet-chemical strategy, using a biomolecule (L-hydroxyproline, L-Hyp) as the green stabilizer and the structure-directing agent. Their morphology, size, composition, crystal structures and growth mechanism were investigated by a series of techniques. The synthesized architectures exhibited enlarged electrochemically active surface area (ECSA), improved catalytic activity, enhanced durability and stability towards ethylene glycol oxidation reaction (EGOR) and glycerol oxidation reaction (GOR) in alkaline electrolytes in comparison with commercial Pd black catalyst.

A polypeptide-mediated synthesis of green fluorescent gold nanoclusters for Fe3+ sensing and bioimaging

In this paper, growth hormone releasing peptide-6 (GHRP-6) is a bioactive polypeptide and acts as the reducing agent and capping ligand for synthesis of bright green fluorescent gold nanoclusters (GHRP-6-Au NCs) by a simple and environmental-friendly aqueous method, with the assistance of NaBr as the fluorescent sensitizer. The obtained GHRP-6-Au NCs had high fluorescent quantum yield (10.7%), and the fluorescence was strongly quenched by the existence of trace Fe3+. Thus, a new and highly sensitive sensor for the assay of Fe3+ was constructed based on the analyte-induced fluorescent quenching mechanism. The sensor had a low detection limit of 1.4µM (S/N=3) and a wide linear range of 2-1000µM. Besides, GHRP-6-Au NCs exhibited low cytotoxicity and high biocompatibility for cell imaging.