AlOOH在一氧化碳加氢反应中结构与性能的研究

采用沉淀水热法,通过调变水热过程中水与凝胶的质量比制备了不同的AlOOH,将其与工业甲醇催化剂C302混合形成复合催化剂,考察复合催化剂对一氧化碳加氢的影响,同时运用XRD、FT-IR、BET、NH_3-TPD-M S、TG-DTG和H_2-TPR等技术对不同AlOOH进行了表征。结果表明,水热过程中水与凝胶的质量比对AlOOH择优取向晶面、孔结构、表面酸强度等存在明显影响,进而导致复合催化剂产物中出现分布不同的低碳醇或二甲醚。其中,当水和凝胶的质量比为2∶1时,AlOOH的(020)和(120)晶面择优取向,孔容增大,且其表面具有适宜的强弱酸比例中心,复合催化剂呈现出较高的低碳醇选择性,表明AlOOH具有碳链增长的作用,这为合成气制取低碳醇催化剂提供了新的思路。

Structure and property of AlOOH in CO hydrogenation

AlOOH were prepared by precipitation-hydrothermal method with different water-to-gel ratios, which were mixed with industrial methanol synthesis catalyst C302 and tested for CO hydrogenation in the fixed-bed reactor. The AlOOH samples were characterized by XRD, FT-IR, BET, NH₃-TPD-MS, TG-DTG and H₂-TPR. The results showed that the ratios of water-to-gel in the hydrothermal process had obvious influence on the preferred orientation, pore structure and surface acidity of AlOOH, leading to the different selectivity of higher alcohols and DME. When the ratio of water-to-gel was 2:1, AlOOH showed in (020) and (120) preferred orientation. Moreover, it had larger pore volume and proper ratio of weak acid sites to strong acid sites, the composite catalyst showed a relatively high selectivity of higher alcohols, which indicated that AlOOH favored the growth of carbon chains. This study provided a new way for synthesis of higher alcohols from syngas.