纳米Pt/TiO_2催化剂上气相CH_3OH光催化分解制氢反应的研究

Study on the Photo-catalytic Decomposition of Methanol Vapor on Pt-loaded Nano-TiO_2 Particles

利用不同还原方法制备了不同纳米粒度的 Pt/TiO2光催化剂, 并且用脉冲氢氧滴定法测定了 TiO2表面 Pt 的分散度. 在气相连续流动装置中利用纳米 Pt/TiO2作为光催化剂, 对气相甲醇的脱氢反应进行了研究. 研究了添加 Pt 和不添加 Pt 的纳米 TiO2, Pt 负载量、铂的不同还原方法、不同 TiO2纳米粒度对气相甲醇光催化分解反应的影响, 并对反应气的空速、光照时间、添加水蒸汽、改变甲醇浓度等与光催化分解甲醇制氢的关系进行了研究, 在最佳反应条件下, 产氢速率达到 5.808 mmol/(g?h). 研究了反应的动力学, 得到该反应为一级反应, 求得了该反应的活化能为 8.53 kJ/mol,并讨论了反应机理.

In the present work, different nano-sized Pt/TiO2 was prepared, and the dispersity of Pt on the surface of TiO2 was measured by hydrogen and oxygen pulse titration method. The photocatalytic decomposition of gaseous methanol on Pt/TiO2 was carried out in a continuous-flow reactor. The effect of various factors on the photocatalysis process was investigated, such as the amount of Pt, different reduction method, different nano-size of TiO2, space velocity, illuminating time, addition of water vapor, methanol concentration, and also the photocatalytic activities of Pt/TiO2 were compared with those of TiO2. One order reaction for methanol decomposition was obtained through the results of kinetics and the activity energy was 8.53 kJ/mol. The reaction mechanism was deduced according to the kinetic and GC/MS analytical results.