Preparation And Catalytic Properties Of Polyacid-based Copper Micro-nano Materials

Combining polyoxometalates(POMs)with metal-based materials produces Nanocomposites with excellent and unique properties.Because of their strong acidity,redox ability,and oxygen-rich surface,POMs have great potential in the field of catalysis.In some cases,metal-based materials add an extra dimension to the functional mix.The Nanocomposites not only combine their respective advantages,but also overcome the disadvantages of POMs,such as intractability,high solubility,and low surface area,to provide synergistic catalysis.In recent years,polyoxometalates-based Nanocomposites have been widely used in many fields such as chemical sensing analysis,electrochemistry,optics,medicine and catalysis due to their unique physical,chemical and hydrodynamic properties.The purpose of this paper is to synthesize polyoxometalates-based Nanocomposites with polyoxometalatess as the basic structural unit,and to study their catalytic properties.Synthesized spindle-shaped copper oxide nanoparticles and polyoxometalate-containing polyoxometalate(POMs=H₃PW₁₂O₄₀(PW₁₂),H₃PMo₁₂O₄₀(PMo₁₂),(NH₄)₃[FeMo₆O₁₈(OH)₆]·7H₂O(FeMo₆))Nanocomposites were characterized by their morphology,structure and composition.Sodium borohydride(Na BH₄)hydrogenation reduction of p-nitrophenol,potassium ferricyanide(K₃[Fe(CN)₆])catalytic reaction and catalytic aryl halide cyanation to study its catalytic activity.(1)Used 2-aminopyridine as reducing agent and template,we explored an inexpensive copper nitrate as a precursor to prepare size and shape tunable spindle-shaped copper oxide nanoparticles(S-CuONPs).By changing n(C₅H₆N₂):n(Cu),the average size can be effectively controlled.The S-CuONPs catalyst showed high catalytic activity in the hydrogenation of 4-NP to 4-aminophenol(4-AP)in the presence of Na BH₄,in addition,the S-CuONPs catalyst was also evaluated in the presence of Na BH₄for catalysis Reduction of K₃[Fe(CN)₆]activity.Cycling experiments using S-CuONPs as catalysts showed that their activities did not decrease significantly in the degradation of 4-NP and K₃[Fe(CN)₆],and exhibits excellent catalytic performance as a promising and efficient catalyst.(2)Used 2-methylimidazole as template regulator,phosphotungstic acid and copper nitrate(Cu(NO₃)₂)as raw materials,Cu-W Nanocomposites with sheet-like structure were synthesized.The structure,morphology and catalytic activity of the Cu-W Nanocomposites were also investigated.The Cu-W Nanocomposites exhibited high catalytic efficiency in catalyzing the hydrogenation reaction of 4-NP,and the results showed that the Cu-W Nanocomposites synthesized at 100?had the fastest catalytic response.The Cu-W Nanocomposites can be recycled for 17 times,and the catalytic conversion rate is maintained above 91%,which indicates that the prepared Cu-W Nanocomposites have excellent catalytic activity and can be recycled for catalytic reduction of nitrophenol compounds.(3)Cu-Mo Nanocomposites were synthesized by co-precipitation method with2-methylimidazole as template,PMo₁₂with Keggin structure and Cu(NO₃)₂as raw materials.The size and morphology of the catalyst were controlled by adjusting the temperature.The morphology,structure and composition of the catalyst were studied by XRD,IR,XPS,N₂adsorption-desorption,SEM,TEM and EDS,respectively.The catalytic efficiency of the Cu-Mo Nanocomposites was evaluated by 4-NP hydrogenation reaction and cyanation reaction of aryl halides,and the results showed that the Cu-Mo Nanocomposites have good catalytic activity and stability.The catalyst can be recycled at least 10 times without significant reduction in conversion rate,has good stability and reusability,and provides a low-cost,simple and practical method for degrading organic pollutants 4-NP and synthesizing benzonitrile compounds,which can be used to advantage in future applications.(4)The Anderson type polyoxometalate FeMo₆was introduced into the ZIF-67framework by coprecipitation method,and FeMo₆@ZIF-67-PVP composite nanomaterials were synthesized.The amount of FeMo₆was adjusted to control the size and catalytic performance of the catalyst,and the synthesized catalyst was characterized and the catalytic activity was tested.The results show that FeMo₆@ZIF-67-PVP composite nanomaterial catalyst has high catalytic activity,showing great application potential as non-noble metal catalyst.