铋铁配比对铁酸铋合成及其光催化性能的影响

EFFECT OF Bi /Fe MOLE RATIO ON THE SYNTHESIS OF BiFeO3AND ITS UV PHOTOCATALYTIC ACTIVITY

采用溶胶凝胶法通过改变原料中铋铁配比合成了以铁酸铋为主相的催化剂粉体。利用定量X射线法分析了不同铋铁配比对铁酸铋合成过程中物相组成的影响。采用紫外-可见光谱表征了粉体的光吸收特性。研究了催化剂组成、光照时间以及催化剂用量对催化降解甲基橙性能的影响。结果表明:九水硝酸铁与五水硝酸铋热分解速率相差较大是引起铁酸铋粉体合成过程中产生杂相的原因。降低铋铁配比有利于铁酸铋相的形成,其中铋铁配比为0.90∶1的原料合成的复合催化剂粉体紫外光降解甲基橙效率最高。

Photocatalyst with BiFeO3as main phase has been prepared by sol-gel method through changing mole ratio of Bi to Fe. The phase composition of the powder has been examined by the quantitative X-ray diffraction. The photo absorbancy was characterized by UV-Vis spectrum. The photocatalytic activity of mixture with BiFeO3as the main phase was investigated by the degradation of methyl orange( MO). Results show that impurity phase has been observed during synthesizing of BiFeO3 because of the huge differences in the decomposition rate of raw material. The content of BiFeO3increases with decreasing mole ratio of Bi to Fe. The powder with Bi∶ Fe = 0. 90∶ 1 exhibits the highest photocatalytic activity. This result has been discussed based on the energy band model of the composite semiconductor.