Abstract: The photocatalytic oxidation of organic compounds using ultrafine semiconductor powder has been one of the most active areas for environmental problems.It is important from the viewpoint of practical applications to develop a simplified kinetic model suitable of representing the very complex mechanisms of photocatalytic oxidation.In the present paper,kinetic analysis is carried out for gas-solid photocatalytic reaction,and a kinetic model is developed.The theoretical results show that the rate of gas-solid photocatalytic reaction is proportional to the light intensity ( I ₀) under low UV light intensity, proportional to the square root of the light intensity under medium UV light intensity,and independent of I ₀ under extremely high UV light intensity.Photocatalytic reaction could be simply decomposed as three continuous processes as follows:photon transfer step, surface action step,and diffusion step.A novel gas-solid photocatalytic reactor is designed,and trichloroethylene is selected as the testing substance.The experimental results show that photon transfer step and surface action step are verified for gas-solid photocatalytic oxidation on nano-TiO₂ powder.

摘要： 对气固相光催化氧化基元反应进行了动力学分析 ,建立了简单适用的动力学模型 .理论分析表明 ,在较低的紫外光强度下 ,光催化反应速率与光强成正比 ;在较高的光强度下 ,速率与光强的平方根成正比 ;在极高光强度下 ,速率与光强无关 .因此将光催化反应简单分解为 3个速率步骤 ,即光子传递步骤、表面作用步骤、扩散步骤 .设计了新颖的气固相光催化反应器 ,采用三氯乙烯 (TCE)为模拟污染物 ,实验结果验证了气固相光催化反应存在光子传递和表面作用控制步骤