铜系催化剂上甲醇蒸气转化制氢过程的原位红外研究

 用原位红外光谱法跟踪研究了不同条件下铜系催化剂上甲醇蒸气转化制氢反应的初始开车过程．结果表明，反应过程中二氧化碳不是在一氧化碳之后产生的．可以推断，铜系催化剂上的甲醇蒸气转化制氢过程不是先进行甲醇分解为一氧化碳和氢气，然后一氧化碳和水蒸气发生变换反应生成二氧化碳和氢气．甲醇蒸气转化反应的主要过程是甲醇和水直接生成二氧化碳和氢气．

Study on Process of Methanol Steam-Reforming to Hydrogen over CuO/ZnO/Al2O3 Catalyst by in Situ Infrared Spectroscopy

Currently, increasing attention has been paid to the process of methanol steam-reforming to produce hydrogen, which has a promising future to be used widely in fuel cells and many other industry fields. But different or contradictory mechanisms concerning the process existed in previous studies. It was suggested that the main issue referring to the reaction mechanism of this process is to find out the relationship between carbon monoxide and carbon dioxide existed in the gas product. In this paper, a transient kinetic method was developed to elucidate the reaction mechanism of methanol steam-reforming. Using this method, the initial start-up of methanol steam-reforming over CuO/ZnO/Al_2O_3 catalyst was monitored by in situ FT-IR directly and timely. Owing to the basic fact that the carbon element in all species in this process stemed only from methanol, every experiment was carried out where water (steam) was fed first and then to feed methanol under different conditions. In all the cases, after feeding methanol to the reaction system, the peaks of IR spectrum for carbon dioxide emerged not behind but before those for carbon monoxide, and the peaks of carbon monoxide appeared almost at the same time when those of methanol vanished. This means that the carbon monoxide is not a main primary product, and therefore it is not the precondition to produce carbon dioxide in the process of methanol steam-reforming. The major reaction included in methanol steam-reforming on CuO/ZnO/Al_2O_3 catalyst should be the reaction of methanol and steam to form hydrogen and carbon dioxide directly, rather than methanol decomposition took place first and then followed by water-gas shift reaction.