Green Controllable Synthesis And Photocatalytic Performance Of Bismuth-Containing Micro/Nano Oxides

Bi2O3 is an important functional material which can act as an important new photocatalyst candidate material due to its unique electronic structure,narrow band gap and chemical stability compared with traditional semiconductor materials such as TiO2 and ZnO.Owing to the great influence of the crystal structure,grain size and morphology of Bi2O3 nanocrystals on their physical and chemical properties,it is of significance to study novel preparation methods to control the sizes and morphologies of micro/nano Bi2O3.In this paper,a green eco-friendly gallic acid(GA)had been used as crystal growth regulator to synthesize a series of micro/nano Bi2O3 and its oxide composites with different structures and morphologies using liquid phase chemical method.The main innovative results are included:1.Three kinds of morphologies of ?-Bi2O3 were synthesized via low temperature liquid phase method using gallic acid as crystal growth modifier,including novel cluster nanowire structure,micron rod structure and micron block structure.Cluster-like nanowires of ?-Bi2O3 with length of 1.5 ?m were synthesised under the conditions of the solution were controlled at pH=10.6 at 40?,pH=10 at 80?,the chemical composition molar ratios of n(GA):n(Bi)=1:1,and the concentration of Bi(NO3)3·5H2O is 0.1 mol/L.In addition,the effect of solution pH,the amounts of gallic acid,the concentration of Bi(NO3)3·5H2O and reaction temperature on the crystal phase and morphology of the product were investigated.The crystal growth mechanism of Ostwald ripening and Oriented attachment was also comfirmed.At the same time,it was found that ?-Bi2O3 nanowire deminstrated an outstanding photodegradation ability to RhB dye under ultraviolet light irradiation.2.?-Bi2O3/SnO2??-Bi2O3/Cu2O??-Bi2O3/ZnO nanocomposites were successfully synthesized on cluster ?-Bi2O3 nanowire matrix.It was found that these three matrix composites could catalyze and degradate RhB dye under visible light.The degradation rate of RhB by ?-Bi2O3/SnO2 reached 65.62%at 2 h,which was higher than pure phase ?-Bi2O3 of 23.58%.3.Micro-spherical Bi2O2CO3 with a diameter of 1?1.5 ?m was successfully synthesized by hydrothermal method using GA as additive chemicals.And further nano?-Bi2O3 was synthesized by low temperature thermal decomposition of Bi2O2CO3 and?-Bi2O3/TiO2,?-Bi2O3/Cu2O composite materials were prepared.Additionally,the growth mechanism of hierarchical microstructure and the effect of the pH of solution,the amounts of gallic acid,reaction temperature on the crystal phase and morphology were explored.Finally,it was found that the composite oxides had shown better photocatalytic activity under visible light irradiation,and the degradation rate of ?-Bi2O3/Cu2O to RhB at 2 h could reach 51.74%.