白钨矿结构BiVO4的水热合成及其可见光催化性能

Hydrothermal Synthesis and Photocatalysis Properties of BiVO4 with Scheelite Structure

摘要:

以Bi(NO₃)₃·5H₂O和NH₄VO₃为原材料, 采用水热法合成了BiVO₄可见光催化材料, 并采用XRD、SEM和UV-Vis等对合成产物的物相结构、形貌、光吸收性能以及光催化性能进行了研究。研究表明,反应体系的pH值对合成产物的物相结构具有重要的影响, 在酸性和弱碱性条件下可获得具有不规则纳米片状形貌的单斜白钨矿结构BiVO₄晶体。合成产物对波长小于525nm的光具有强烈的吸收。水热条件的不同直接影响着产物对甲基橙溶液的可见光催化降解性能, 在Bi∶V比例为1∶1, 同时pH值为3.08并于160℃下水热处理1h所合成的BiVO₄晶体对甲基橙溶液具有最佳的可见光催化活性。

Abstract:

The visible-light responsive photocatalyst BiVO₄ crystals were prepared via a hydrothermal synthesis with Bi(NO₃)₃·5H₂O and NH₄VO₃ as the raw materials. The crystal structure, particle size, morphologies and optical properties of the as-synthesized samples were investigated by XRD, SEM and UV-Vis tests. The results reveal that pH value of the precursor solution plays an important role in determining the phase of the as-synthesized products. The XRD and SEM results of the products which were synthesized under acidic or weak alkaline condition show that those samples possess a pure monoclinic scheelite structure of BiVO₄, and exhibite irregular lamellar-like shape. The absorption edge of the as-prepared BiVO₄ crystals is located at 525nm. The reaction conditions have significant influence on the photocatalytic property of the as-synthesized products. When Bi∶V is 1∶1, pH value is 3.08, temperature is 160℃, and hydrothermal treatment time is 1h, the photocatalytic activities reach the maximum.