Morphologh Control Synthesis And Catalytic Properties Research Of Copper Oxide Nanoarrays

The copper oxide nanomaterials play an important role in many fields,such as catalysis, sensors, lithium, and biomimetic materials. The currentresearch is focused on the morphology control synthesis of copper oxidenanomaterials, the growth mechanism, and the relationship between themorphology and performance. In particular, the development of thenanomaterial arrays which have the same crystal planes and uniform sizes canprovide the scientific basis for the further applications in nanodevices. Herein,a series of copper oxide (CuO) nanoarrays materials with differentmorphologies, sizes and crystal planes were prepared, characterized and usedas structured catalysts in phenol oxidation reactions. The results revealed thatthe composition, morphology and structure of CuO nanoarrays obviouslyinfluenced on catalytic properties, and discussed the relation of crystal planeeffect and catalytic performance. These structured catalysts exhibited highactivity, good stability, easy separation, simple preparation process and otheradvantages, which had a potential application value in the future industrial application. The main research results are as follows:1. By in situ growth method, the copper foil and foam copper wereselected as substrates for the controllable synthesis of CuO nanoarraysstructures with different morphologies, including nanosheets, nanobelts, andnanowires. Their compositions and structures were characterized by XRD,SEM, TEM, XPS and TPR. In the phenol oxidation by H2O2, three kinds ofCuO structures exhibited different catalytic performances, in which thesheet-like CuO showed the highest conversion, and that of the wire-like onewas minimum. We revealed the relationship between crystal plane on catalyticproperty: the nanosheets arrays exposed by [1-10] plane showed a bettercatalytic activity than the nanoribbons with the exposed [001] planes, and thenanowires seemed not to be a sing-crystalline structure. A mathematicalsimulation model was built and demonstrated our conclusion.2. By extra addition method of copper source, the glass, copper foam, andnickel foam were used as substrates for the hydrothermal synthesis of copperoxide nanoarrays structures with various morphologies. SEM, TEM andHRTEM were utilized to investigate crystal structures and morphologies,and the effect of different experimental conditions on morphology andperformance, for instance substrate, copper sort, and concentration, wasinvestigated. It was found that copper nitrate as copper source and glass assubstrate were the optimized conditions, under which CuO nanoarrays had thebest catalytic activity, but its stability was not as good as the former samples by in situ growth. It was mainly because the active component CuO had a poorbonding force with the substrates by the exta copper salts.3. By the introduction of cerium dioxide, the CuO nanoarrays andpowders were modified and the effect of cerium on Cu in phenol oxidationreaction were carefully studied. The film of cerium oxide loading on thesurface of CuO nanoarrays were prepared by spin-coating method andfollowed by calcination, while catalytic activity of CuO catalysts was notobviously improved which might be related to a uneven dispersion of ceriumoxide on the surface. Alternatively CeO2could be uniformly introduced intothe structures of CuO nanopowders using Ce-containing layered doublehydroxides as precursors, and their thermal stability, catalyst activity andselectivity could be significantly improved.