Sea-Island-Like Morphology of CuNi Bimetallic Nanoparticles Uniformly Anchored on Single Layer Graphene Oxide as a Highly Efficient and Noble-Metal-Free Catalyst for Cyanation of Aryl Halides

Copper-Based Integral Catalytic Impeller for the Rapid Catalytic Reduction of 4-Nitrophenol

The integral catalytic impeller can simultaneously improve reaction efficiency and avoid the problem of catalyst separation, which has great potential in applying heterogeneous catalysis. This paper introduced a strategy of combining electroless copper plating with 3D printing technology to construct a pluggable copper-based integral catalytic agitating impeller (Cu-ICAI) and applied it to the catalytic reduction of 4-nitrophenol (4-NP). The obtained Cu-ICAI exhibits very excellent catalytic activity. The 4-NP conversion rate reaches almost 100% within 90 s. Furthermore, the Cu-ICAI can be easily pulled out from the reactor to be repeatedly used more than 15 times with high performance. Energy-dispersive spectrometry, X-ray diffraction, and X-ray photoelectron spectroscopy characterizations show that the catalyst obtained by electroless copper plating is a ternary Cu-Cu₂O-CuO composite catalyst, which is conducive to the electron transfer process. This low-cost, facile, and versatile strategy, combining electroless plating and 3D printing, may provide a new idea for the preparation of the integral impeller with other metal catalytic activities.

Corrosion and transformation of solution combustion synthesized Co, Ni and CoNi nanoparticles in synthetic freshwater with and without natural organic matter

Pure metallic Co, Ni, and their bimetallic compositions of Co3Ni, CoNi, and CoNi3 nanomaterials were prepared by solution combustion synthesis. Microstructure, phase composition, and crystalline structure of these nanoparticles (NPs) were characterized along with studies of their corrosion and dissolution properties in synthetic freshwater with and without natural organic matter (NOM). The nanomaterials consisted of aggregates of fine NPs (3-30 nm) of almost pure metallic and bimetallic crystal phases with a thin surface oxide covered by a thin carbon shell. The nanomaterials were characterized by BET surface areas ranging from ~ 1 to 8 m2/g for the Ni and Co NPs, to 22.93 m2/g, 14.86 m2/g, and 10.53 m2/g for the Co3Ni, CoNi, CoNi3 NPs, respectively. More Co and Ni were released from the bimetallic NPs compared with the pure metals although their corrosion current densities were lower. In contrast to findings for the pure metal NPs, the presence of NOM increased the release of Co and Ni from the bimetallic NPs in freshwater compared to freshwater only even though its presence reduced the corrosion rate (current density). It was shown that the properties of the bimetallic nanomaterials were influenced by multiple factors such as their composition, including carbon shell, type of surface oxides, and the entropy of mixing.