Hanfan Liu

Shape-controlled synthesis of palladium nanocrystals by microwave irradiation

The controlled synthesis of Pd icosahedra in tetraethylene glycol (TEG) with H2PdCl4 as a precursor and poly(vinylpyrrolidone) (PVP) as a stabilizer in the presence of an appropriate amount of KOH under microwave irradiation was demonstrated. TEG served as both solvent and reducing agent, and stable Pd icosahedra with uniform sizes and well-defined shapes could be prepared in a yield of over 90 % by microwave heating for 60 s. The sizes of Pd icosahedra can be well controlled by adjusting the concentration of the precursor H2PdCl4.

Controlled synthesis of hierarchical tetrapod Pd nanocrystals and their enhanced electrocatalytic properties

Well-defined highly branched hierarchical tetrapod Pd nanocrystals with mutually embedded metameres were successfully synthesized with Pd(acac)2 as a precursor and CO as a reducing agent in the presence of SDS. SDS played an essential role in controlling the hierarchical tetrapod morphologies of the final products. The formation of the hierarchical Pd tetrapods was ascribed to the SDS-confined growth from the four tips along the directions. The as-prepared hierarchical Pd nanostructures demonstrated outstanding electrocatalytic activity.

Controlled synthesis of Pd–Pt alloy nanohypercubes under microwave irradiation

Pd–Pt alloy hypercubic nanostructures were successfully fabricated by reducing Pd and Pt precursors simultaneously in a one step process under microwave irradiation for only 100 s without using any sacrificial templates. Together with the use of tetraethylene glycol (TEG) as both a solvent and a reducing agent, the presence of KI was critical to the formation of Pd–Pt alloy nanohypercubes. The as-prepared Pd–Pt alloy nanohypercubes improved the electrocatalytic activities.

Controlled synthesis of tetrapod/Mitsubishi-like palladium nanocrystals

Well-defined tetrapod/Mitsubishi-like Pd nanocrystals with uniform dimensions were successfully synthesized by using Pd(acac)2 as a precursor and CO as a reducing agent in the presence of sodium acetate. Carboxylate anions such as acetate anions played an essential role in controlling the tetrapod morphologies of the final products.

Controlled Synthesis of Hierarchical Pd Nanodendrites and Their Electrocatalytic Properties

Well-defined hierarchical Pd nanodendrites with (111) surface were successfully synthesized with Pd(acac)2 as a precursor, polyvinylpyrrolidone (PVP) as a stabilizer, CO as a reducing agent in the presence of appropriate amounts of NaAc and oleylamide (OAm) at 100 °C for 3 h under atmospheric pressure. OAm played an important role in controlling the growth of the hierarchical dendritic nanostructures of the final products. The formation of the hierarchical Pd dendrites was ascribed to the OAm-confined growth from the tips along 〈111〉 axis directions. This kind of hierarchical Pd nanodendrites exhibited an enhanced electrocatalytic activity for the electro-oxidation of formic acid compared with Pd black.

One-pot synthesis of hierarchical concave tetrapod Pd nanocrystals and their electrocatalytic properties

Well-defined Pd nanocrystals with both hierarchical pods and concave centers were synthesized by reducing Pd(acac)2 with CO in the presence of polyvinylpyrrolidone and oleylamine in DMF. Oleylamine was responsible for the generation of the hierarchical concave tetrapod Pd nanostructures. The as-prepared novel Pd nanocrystals demonstrated highly enhanced electrocatalytic activity.

Facile synthesis of self-assemblies of ultrathin round Pd nanosheets or nanorings and their enhanced electrocatalytic activities

Self-assemblies consisting of ultrathin round Pd nanosheets with a thickness of three to six atomic layers for an individual Pd nanosheet are fabricated in a one-pot process by reducing Pd(acac)2 with CO as a reducing agent in the presence of sodium acetate at 100 °C for 3 h. The synergistic effect of CO and acetate ions is crucial to the formation of the ultrathin round Pd nanosheet self-assemblies. The selective adsorption of I− ions on the side (100) faces as well as CO on the (111) flat surfaces results in the production of Pd nanosheets, while the van der Waals forces between acetate ions adsorbed on the surfaces of the nanosheets promote the formation of a self-assembly of Pd nanosheets. Based on the Pd nanosheet self-assemblies, Pd nanoring self-assemblies are generated by means of oxidative etching arising from I−/O2 pairs. Both the as-prepared self-assemblies of ultrathin round Pd nanosheets and the self-assemblies of Pd nanorings exhibit outstanding electrocatalytic activities.

SHAPE-CONTROLLED SYNTHESIS OF RUTHENIUM NANOPARTICLES

Uniform pompon-like Ru nanoparticles with an average diameter of 148 nm were readily synthesized by reducing RuCl3 with triethylene glycol (TG) as both a reducing agent and a solvent in the presence of PVP by oil-bath heating at 170°C for 6 h. The as-prepared Ru nano-pompons were characterized by TEM, XRD, XPS and UV-vis absorption spectroscopy. The effects of some parameters such as the average molecular weight and the concentration of PVP on the synthesis of Ru nano-pompons were investigated.

Platinum Nanoparticle–Based Assay for Proteins by Resonance Light Scattering

ABSTRACT A simple, sensitive, platinum nanoparticle–based assay for trace amounts of protein by resonance light scattering (RLS) was studied. The RLS intensities for bovine serum albumin (BSA) and human serum albumin (HSA) were remarkably enhanced due to the interaction with Pt nanoparticles at pH 3.5 or 4.0, respectively, and the maximum RLS peak appeared at 390 nm. The RLS intensity increased proportionally with Pt concentration below 3.0 × 10−5 mol · L−1 but declined gradually above 4.0 × 10−5 mol · L−1. BSA within the range 0.1–3.0 µg · mL−1 and HSA of 0.1–2.7 µg · mL−1 can be detected with this method, and the detection limits were 4.2 and 10.7 ng · mL−1, respectively. The method was satisfactorily applied to the quantitative determination of total proteins in human serum samples with a maximum relative standard deviation (RSD) lower than 2.8% and recoveries in the range 100.4–102%.