Xiaofei Yu

PtM (M=Cu, Co, Ni, Fe) Nanocrystals: From Small Nanoparticles to Wormlike Nanowires by Oriented Attachment

Pt-M (M = Cu, Co, Ni, Fe) wormlike nanowires with excellent catalytic activities were produced by a hydrothermal method. Based on the experiment results, Pt-M nanoparticles grew into nanowires through oriented attachment. The electrocatalytic activities of these nanowires toward methanol oxidation were also studied by cyclic voltammetry and chronoamperometry measurements. The synthesized Pt-M nanowires showed higher catalytic activity and stability for methanol oxidation than Pt nanowires and commercial Pt black.

Platinum–Copper Nanoframes: One‐Pot Synthesis and Enhanced Electrocatalytic Activity

Platinum-copper nanoframes were produced from copper nanoparticles by a one-pot synthesis method. The growth mechanism was thoroughly studied by experiment and theoretical calculations. Owing to the unique structure, Pt-Cu nanoframes exhibited significantly enhanced catalytic activity toward the electro-oxidation of methanol compared to commercial Pt black.

Synthesis and electro-catalytic activity of Pt-Co nanoflowers

The study of metallic nanoflowers has attracted more and more attention because of their larger surface areas and active sites, which could be applied for surface-sensitive areas. Despite these excellent characteristics, it is still very hard to synthesize noble metal nanoflowers as the flower-like structure is apt to change into some more stable shapes which are covered by lower energy surfaces. In this study, Pt-Co nanoflowers were successfully synthesized by a two-step method via the reaction between Co nanoparticles and Pt precursor. From the transmission electron microscopy (TEM) images, it could be seen clearly that the products possessed a flower-like nanostructure. The morphology of the final products depended on a number of parameters, such as the reaction time and the reaction temperature. Based on the experimental results and theoretical calculation, the formation of nanoflowers could be attributed to the galvanic replacement reaction between Co nanoparticles and Pt precursor. In addition, the electrochemical catalytic activity of Pt-Co nanoflowers toward methanol oxidation was also evaluated in comparison with that of commercial Pt black. Owing to the special structure, the electro-catalytic activity and stability of Pt-Co nanoflowers were much better than those of commercial Pt black.

Removal of Cr(III)/Cr(VI) from wastewater using defective porous boron nitride: a DFT study

Developing highly-efficient adsorbent materials for the removal of Cr(III)/Cr(VI) ions from industrial wastewater is of great importance for environmental pollution control. In this work, density functional theory was used to model the adsorption capacities of Cr(III)/Cr(VI) ions on defective porous boron nitride (p-BN). Our results suggest that both nitrogen (VN) and boron (VB) vacancies contribute to the adsorption of Cr(III)/Cr(VI) ions on p-BN. In the case of a VN defect, the calculated adsorption energy (Eads) values are 3.76 eV and 4.58 eV for single Cr(III) and Cr(VI) ions, respectively, whereas, in the case of a VB defect, the Eads values are 8.55 eV and 10.26 eV for Cr(III) and Cr(VI) ions, respectively. The analysis of the electronic structure reveals that defective levels in the energy gap region strongly affect the adsorption performance of p-BN as an adsorbent. More importantly, we clarify that the strong adsorption of Cr(III)/Cr(VI) ions on defective p-BN is indeed chemical adsorption and not dispersion or electrostatic attraction. High coverage of Cr(III) and Cr(VI) ions and the effect of water solvent molecules were also taken into account. These findings indicate that defective p-BN is an excellent candidate for the removal of Cr(III)/Cr(VI) ions from wastewater.