Chen Chun-Liang, Wang Ching-Huei, Weng Hung-Shan
Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan.
Chemosphere. 2004 Aug;56(5):425-31. doi: 10.1016/j.chemosphere.2004.04.006.
This work is for the purpose to find a high performance catalyst for the catalytic reduction of SO2 with H2 as a reducing agent. NiO/gamma-Al2O3 catalyst was found to be the most active catalyst among the seven gamma-Al2O3-supported metal-oxide catalysts tested. With NiO as the active species, of the supports tested, gamma-Al2O3 was the most suitable one and the optimal Ni content was 16 wt%. Using this NiO/gamma-Al2O3 catalyst, we found that the optimal feed ratio of H2/SO2 is 2:1 and the catalyst presulfided with H2 + H2S exhibits a higher performance than that pretreated with H2 or He. XRD patterns reveal that the nickel oxide experienced a transformation to Ni3S2 and NiS, and then to NiS2, the most active nickel sulfide, during the reaction process. The reason for the highest catalyst activity of 16 wt% Ni was attributed to the largest amount of NiS2. Water vapor in the feed gas reactant caused inhibition of catalyst activity, whereas H2S promoted the reduction of SO2. These phenomena were rationalized with the aid of Claus reaction.
这项工作的目的是寻找一种以氢气作为还原剂催化还原二氧化硫的高性能催化剂。在测试的七种γ-氧化铝负载的金属氧化物催化剂中，发现NiO/γ-氧化铝催化剂是活性最高的催化剂。以NiO作为活性组分，在所测试的载体中，γ-氧化铝是最合适的，最佳镍含量为16 wt%。使用这种NiO/γ-氧化铝催化剂，我们发现氢气与二氧化硫的最佳进料比为2:1，用氢气+硫化氢预硫化的催化剂表现出比用氢气或氦气预处理的催化剂更高的性能。X射线衍射图谱表明，在反应过程中，氧化镍经历了向Ni3S2和NiS的转变，然后转变为活性最高的硫化镍NiS2。16 wt%镍的催化剂活性最高的原因是NiS2的量最大。原料气反应物中的水蒸气会抑制催化剂活性，而硫化氢则促进二氧化硫的还原。借助克劳斯反应对这些现象进行了合理的解释。
