Jun-Yan Gong

Synthesis of copper/cross-linked poly(vinyl alcohol)(PVA) nanocables via a simple hydrothermal route

Cross-linking reaction of poly(vinyl alcohol) n (PVA) can be initiated in the presence of copper ions, resulting in the formation of copper@cross-linked PVA nanocables by a one-step hydrothermal approach. In contrast to our previous findings in the case of silver ions, metal ions with high valency are more difficult to reduce during the cross-linking reactions under hydrothermal conditions. The variation of pH value during the reaction has significant effects on the quality of the product. Copper@cross-linked PVA nanocables with a diameter of 0.5–1 µm and length up to 100 µm can be obtained at 200 °C, accompanying the presence of some cross-linked PVA aggregates with near spherical shape and irregular shape. The pH value, reaction temperature, and reaction time play key roles in the formation of such nanocables. The results demonstrated that the cross-linking reaction in the presence of different metal ions has different reaction rates, which determine the uniformity of the product and the quality of the cable-like core–shell structures.

A general approach for synthesis of a family of functional inorganic nanotubes using highly active carbonaceous nanofibres as templates

A family of functional metal oxide nanotubes such as TiO2, Fe2O3, SnO2, ZrO2, and SnO2@Fe2O3 composite can be successfully fabricated by using highly active carbonaceous nanofibres as templates, which are synthesized via a hydrothermal approach. Compared with the previous strategy of using carbon nanotubes as templates, the carbonaceous nanofibres synthesized by the hydrothermal approach have higher reactivity, thus making them more suitable for templating synthesis of a variety of metal oxide nanotubes. This general method can be further developed to synthesize uniform ternary oxide nanotubes such as BaTiO3 and metal oxide composite nanotubes. The gas sensitivity of SnO2nanotubes synthesized by this approach has showed higher sensitivity, which exemplifies the distinct properties of such 1D hollow nanostructures. These uniform nanotubes might find potential applications in fields such as catalysis, chemical/biological separation, and sensing.

Large scale synthesis of uniform silver@carbon rich composite (carbon and cross-linked PVA) sub-microcables by a facile green chemistry carbonization approach

A facile green chemistry carbonization method has been discovered for the synthesis of uniform silver@carbon rich composite (carbon and cross-linked polyvinyl alcohol) core-shell sub-microcables in large quantities, where the carbon sources such as glucose-based saccharides have played important roles in the formation of these novel sub-microcables.

Controllable Synthesis of VSB‐5 Microspheres and Microrods: Growth Mechanism and Selective Hydrogenation Catalysis

Nanoporous VSB-5 nickel phosphate molecular sieves with relatively well controllable sizes and morphology of microspheres assembled from nanorods were synthesized at 140 degrees C over a short time in the presence of hexamethylenetetramine (HMT) by a facile hydrothermal method. The pH value, reaction time, and ratio of HMT to NaHPO2.H2O crucially influence the morphology and quality of the final products. By adjusting the pH value of the initial reaction solution, the morphology changes from disperse rods to microspheres assembled from rods and finally to a large quantity of fibers, and the diameters of the VSB-5 rods can be varied. The catalytic activity of VSB-5 in selective hydrogenation of several unsaturated organic compounds was tested. Nickel(II) in VSB-5 can selectively catalyze hydrogenation of C=C in trans-cinnamaldehyde and 3-methylcrotonaldehyde. In addition, since nitrobenzene (NB) and 2-chloronitrobenzene could be reduced to aniline (AN) and 2-chloroaniline with high selectivity, VSB-5 could have potential applications in synthesizing dyes, agrochemicals, and pharmaceuticals.