Nb2O5纳米纤维的物相对光催化性能的影响

Structure-dependent Photocatalytic Properties of Nb_2O_5 Nanofibers

采用静电纺丝技术在不同退火条件下制备不同物相的Nb2O5纳米纤维,研究了产物的物相对光催化染料降解性能的影响。光吸收结果表明,伪六方相Nb2O5纳米纤维的光学带隙为2.77eV,单斜相为主的混合相Nb2O5纳米纤维带隙为2.51eV。在混合相材料中,光学带隙随着单斜相成分的增加而改变。光催化结果表明,伪六方相Nb2O5纳米纤维具有最高的光催化活性,其效率k值可达-0.025min-1。混合相纳米纤维中,单斜相的增加会引起催化活性的变化,其变化趋势与带隙相符。物相对Nb2O5纳米纤维光催化活性的影响可归结于带隙变化引起的入射光吸收效率和电子空穴对氧化能力的变化。

The Nb205 nanofibers with different structures were synthesized by electrospinning process under different annealing conditions. The effect of structure on the photocatalytic properties for dye degradation of the pro- ducts was investigated. The absorption results showed that the energy band gap of quasi-hexagonal phase of Nb20s nanofibers was 2. 77 eV, while that of the nanofibers with monoclinic phases as the major phase was 2. 51 eV. The in- creasing of monoclinic phase in the monoclinic-orthorhombic system led to the change of band gap. The results of pho- tocatalytic experiment showed that the quasi-hexagonal Nb2O5 nanofibers exhibited the highest photocatalytic activity with k value of -0. 025 min-1. The increasing of monoclinic phase in the mixing system also resulted in the similar changes of the photocatalytic properties. The structure-dependent photocatalytic properties of the Nb2O5 nanofibers should be attributed to the variations of the absorption efficiency to the incident light as well as the oxidation capacity of the electron-hole in the nanofibers, both of which are induced by the changing of energy band gaps.