Pt/TiO2上苯和乙烯光催化氧化过程的磁场效应

以Pt/TiO₂为催化剂和365 nm紫外光为光源, 在低于0.2 T的磁场强度范围考察了磁场对苯和乙烯光催化氧化反应的影响. 实验发现, 当用紫外灯管作光源并靠近磁场磁极或者置于磁场磁极间隙内照射反应器时, 磁场可显著提高气相苯和乙烯的光催化转化率和矿化率; 而当光源远离磁场磁极而通过光导纤维传导照射到反应器上时, 磁场对这两个反应没有促进作用. 在前一种情况下, 紫外灯管的发光强度随磁场的增强而提高, 磁场对这两个光催化降解反应的促进作用被证实是由于磁场提高了紫外灯管的发光强度, 进而为反应提供了更多的光能和使反应温度升高所致；在后一种光照方式下, 由于光源不受磁场影响, 磁场对这两个光催化反应不产生影响. 这一研究结果表明, 在所研究磁场强度范围, 磁场对气-固相光催化反应没有任何本征影响.

Effect of Magnetic Field on the Photocatalytic Oxidation of Benzene and Ethylene over Pt/TiO2

The effect of magnetic field on the photocatalytic oxidation of benzene and ethylene contained in air over Pt/TiO₂ was studied under 365 nm irradiation in the range of magnetic field intensity of ≤0.2 T. It was found that when the UV lamp was near to or under a magnetic field, the magnetic field could enhance the photocatalytic conversion and mineralization of benzene and ethylene. However, no effect of magnetic field on the reactions was observed when the UV lamp was far away from the magnetic field and the light was transmitted onto the reactor by a focusing fiber. In the former case, the observed enhance of photocatalytic oxidation of the two reactants was a result of the increase of brightness of the UV lamp under magnetic field. This is because that high photo intensity provided high light energy for the reaction and led to increase of the reaction temperature. In the latter case, intensity of UV light wasn′t disturbed by the magnetic field, applying magnetic field had no effect on the two photocatalytic reactions. The results showed that there was no any inherent effect on the gas-solid phase photocatalytic reaction.