Synthesis of Novel Pd Nanosponges for Non-Enzymatic Glucose Sensor.

A unique nanostructured electrocatalyst based on Palladium (Pd) nanosponge architecture is synthesized by one-step dealloying of the amorphous alloy precursor with low Pd concentration. The sponge-like nanostructure with hollow interiors enables sufficient contact between reactants andboth the interior and exterior surfaces. The results of cyclic voltammetry reveal that the as-prepared Pd nanosponge exhibits high sensitivity of 32 µA mM-1 cm-2 in a wide linear range (1-18 mM), and long-term stability toward glucose electro-oxidation. The Pd nanosponge also manifests detection limit as low as 2.0 µM (S/N = 3) and high selectivity for glucose sensing. The enhanced catalytic activity of the Pd nanosponge is attributed to the bimetallic synergistic effect and the large active surface area of the high-uniformity porous structure. The facile synthesis of the cost-effective Pd nanosponge with superior electrocatalytic performance makes it hold great potentials for biosensor and other catalysis applications.

Refinement of Nanoporous Copper with Poly(vinyl alcohol) During Dealloying Amorphous Mg65Cu25Y10 Precursors.

Ultrafine nanoporous copper (UNP Cu) with a characteristic pore size of about 12 nm and a ligament size of about 14 nm was fabricated from amorphous Mg65Cu25Y10 precursor alloys after dealloying in a 0.1 M H2SO4 solution modified by poly(vinyly alcohol) polymers with a molecular weight of 105000 g/mol (PVA-124). The suppression of the surface diffusion from PVA-124 reduced the size of the nanopores and ligaments to 20 nm when the concentration of the added PVA-124 exceeded 0.1 g L-1. When the concentration of the added PVA-124 exceeded 2 g L-1, PVA-124 triggered the polymerization process. The resultant polymer surface layer on the fcc Cu ligaments was shown to reduce the rate of selective dissolution. It was also shown that extending the immersion time resulted in a suppression of coarsening. The introduction of PVA-124 polymer into acids resulted in a higher viscosity of the dealloying solutions, particularly when the concentration of PVA-124 was higher than 1.0 g L-1. This viscosity was shown not only to reduced rate of diffusion of Cu adatoms in PVA-124 solutions, but also forced the accumulation of Cu adatoms to form small scale UNP Cu.

Adsorptive removal of dibenzothiophene from model fuels over one-pot synthesized PTA@MIL-101(Cr) hybrid material.

Hybrid nanomaterials comprising phosphotungstic acid (PTA) and MIL-101(Cr) were prepared through one-pot synthesis and post-modification methods and then were used as adsorbents of dibenzothiophene (DBT) from simulated diesel fuels. Samples obtained by different ways (encapsulation and impregnation) were characterized by nitrogen adsorption, transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform infrared spectrum (FT-IR) and series of adsorption experiments. The equilibrium adsorption capacities of PTA@MIL-101(Cr) illustrated that the direct introduction of PTA into MIL-101(Cr) during synthesis resulted in a 10.7% increase compared with MIL-101(Cr). However, porous hybrid adsorbent PTA/MIL-101(Cr) prepared via post-modification method exhibited lower adsorption capacity than virgin MIL-101(Cr). The theoretical maximum adsorption capacity (Q0) of PTA@MIL-101(Cr) is 136.5mg S/g adsorbent, 4.2 times of MIL-101(Cr). Even in competitive adsorption between aromatic compounds, which possess strong affinity with MOFs, and DBT, PTA@MIL-101(Cr) and MIL-101(Cr) remained their effectiveness in removal of DBT in the system. Based on these results, it can be presumed that MIL-101(Cr), modified properly, can be used as a promising adsorbent for eliminating aromatics and S-compounds in commercial fuels simultaneously.