TiO2、BiVO4、Cu2O光催化降解低浓度甲醛

比较研究了3种（TiO2，BiVO4，Cu2O）光催化剂对低浓度甲醛的降解过程，拟通过结构分析（晶粒尺寸、比表面积、禁带宽度）和实验评价其性能优劣，优选出光催化性能较好的材料。通过结构分析和降解甲醛实验发现，甲醛初始浓度较低时，BiVO4降解率优于其他，随甲醛浓度增加，催化剂降解率均呈上升趋势，TiO2-1（T-1）、TiO2-2（T-2）降解率增加显著。随环境湿度增大，降解率先上升后下降，BiVO4-1（B-1）、BiVO4-2（B-2）降解率下降的较为缓慢。同一物质当晶粒尺寸越小比表面积越大，其降解率越好。T-2比B-1有更好的稳定性。分析认为在较低甲醛浓度时，决定光催化降解率的主要因素是催化剂的表面反应速率。随着甲醛初始浓度的增加，吸附脱附成为主要限制步骤。随环境湿度增加，甲醛降解率先上升后下降，具有较小比表面积的BiVO4降解甲醛效率下降不显著。连续的工作产生甲醛分解副产物，不易堵塞具有大比表面积的T-2的活性位点，所以T-2有更好的稳定性。

Photocatalytic degradation of low concentration formaldehyde by TiO2, BiVO4 and Cu2O

This paper compared the catalytic degradation effects of the three photocatalysts (TiO2, BiVO4, Cu2O) on low concentration formaldehyde. In order to select materials with better photocatalytic properties, structure analysis and experimental were conducted,which related to crystal size, specific surface area and band gap. By analyzing the structure and degradation of formaldehyde, it was found that the degradation efficiency of all of the catalysts showed an upward trend and TiO2-1(T-1),TiO2-2(T-2) increased significantly with increasing concentration of formaldehyde.With the environment humidity increased,the degradation efficiency of the catalysts were first increased and then decreased. BiVO4-1(B-1),BiVO4-2(B-2) degradation rate decreased more slowly. The same material as the grain size is smaller, the greater the specific surfacearea,having the higher degradation rate.T-2 had a better stability than B-1. It was analysis that the main factor influencing the photocatalytic degradation rate is the surface reaction rate of the catalyst at low concentrations of formaldehyde. With the increase of initial concentration of formaldehyde, the adsorption and desorption become a major limiting step. With increasing humidity, the formaldehyde degradation rises up and then falls down. The decrease in degradation of formaldehyde is not significant for the BiVO4 with small specific surface area. After work continuously to produce formaldehyde by-products,it was not easy to block T-2 which had larger the surface area the active site. So T-2 had a better stability.