激光促进乙烯在硫酸镍上表面反应

Laser Stimulated Surface Reaction of C_2H_4 on Nickel Sulfate

制备了硫酸镍固体材料．采用红外光谱（ＩＲ）、程序升温脱附（ＴＰＤ）和激光促进表面反应（ＬＳＳＲ）技术，研究了乙烯在ＮｉＳＯ４表面上的化学吸附态和激光促进Ｃ２Ｈ４表面反应性能．实验结果表明，Ｃ２Ｈ４以Ｈ原子与固体材料表面Ｌｅｗｉｓ碱位（Ｓ＝Ｏ键中的端氧）作用，形成分子吸附态．在常压和 １００℃条件下，用 １０７９ ｃｍ－１激光激发吸附有Ｃ２Ｈ４分子中Ｈ的Ｓ＝Ｏ键１００次，Ｃ２Ｈ４转化率可达１５％，生成丁二烯的选择性为１００％．根据表征和反应结果，讨论了Ｃ２Ｈ４在ＮｉＳＯ４上的ＬＳＳＲ机理和影响ＬＳＳＲ性能的因素．

Solid material NiSO4 was prepared. A TEA-CO2 laser generator was adopted as the light source to carry on laser stimulated surface coupling reaction of ethylene. The infrared vibration structure and adsorption state of C2H4ad--NiSO4 system were discussed based on infrared and temperature programmed desorption tests. It was showed that C2H4 is adsorbed as molecular state, bonding with NiSO4 surface through H atom at terminal O of S =O. The 1 079 cm-1 laser was selected to activate solid surfacial bond S =O, which absorbs the photon energy efficiently. At normal pressure and a temperature below 100 ℃, C2H4 conversed to butadiene with a high selectivity of 100%. Increasing laser pulse can improve conversion of C2H4 without change of selectivity. After 200 pulses, C2H4 in the system had been consumed to a large extent, and the product occupied most of the surface active sites, therefore conversion of C2H4 increased at a low speed. Temperature can also affect the laser stim-ulated surface reaction of C2H4ad-NiSO4. At 100 ℃, 15. 1% of C2H4 convert to butadiene, while keeping high selectivity of 100%. Based on the above experimental results, a mechanism of LSSR was proposed for the conversion of C2H4 to C4H6.