中文摘要：

近年来,氢能作为清洁可再生新型能源越来越受到人们关注.然而,氢气储存和运输困难,制约了其广泛利用.因此,寻找一种高效的原位在线制氢技术成为解决这一难题的重要方案之一.二甲醚作为氢的载体,具有高H/C比、高能量密度、无毒和无致癌性等优点,而且二甲醚的物理性质与液化石油气（LPG）相类似,燃烧时不会产生污染性气体,且工业上已实现大规模生产.通过重整技术,可以使二甲醚有效地转化为H2.目前的重整技术主要包括部分氧化重整、自热重整、干重整以及水蒸气重整（SR）.其中二甲醚水蒸气重整（DMESR）技术具有很高的氢气产率,被认为是一种非常有前途的在线制氢技术.二甲醚水蒸气重整反应分两步进行,第一步是固体酸催化剂催化的二甲醚水解反应,第二步是金属催化剂催化的甲醇水蒸气重整反应.其中二甲醚水解反应是整个反应的控速步骤.γ-Al2O3作为一种最常用的固体酸催化剂,因其在二甲醚水蒸气重整反应中的良好活性和稳定性,以及很少的副反应等优点,得到了国内外研究者的普遍青睐.但是,γ-Al2O3催化二甲醚水解反应的温度较高（300–400℃）,极易导致用于重整的铜基催化剂烧结和失活.与γ-Al2O3相比,H型分子筛催化剂（如HZSM-5）酸性较强,酸性位较多,催化二甲醚水解反应的温度要低得多（〈300℃）.然而HZSM-5含有的强酸位在二甲醚水蒸气重整过程中极易导致催化剂因积碳而失活.因此,有必要对HZSM-5分子筛进行改性,去除不必要的强酸位,以降低积碳,提高催化剂的活性和稳定性.本文利用HZSM-5良好的离子交换能力,在不改变分子筛骨架结构的前提下,通过一种简单的浸渍法制备了一系列不同P含量的P改性HZSM-5催化剂,并分别将其与传统的CuO-ZnO-Al2O3催化剂机械混合用于二甲醚水蒸气重整制氢.详细研究了P改性对HZSM-5分子筛酸性以及P-HZSM-5/

英文摘要：

Dimethyl ether steam reforming （DME SR） was catalyzed by a CuO-ZnO-Al2O3 （CuZnAlO） catalyst mixed with P-modified HZSM-5 for the production of H2. The effect of P modification on the acidity and activity of the P-HZSM-5/CuZnAlO mixed catalyst for DME SR was investigated. P-HZSM-5/CuZnAlO gave a higher CO2 selectivity and also higher stability during DME SR compared to the mixed catalyst with HZSM-5. N2 desorption, X-ray diffraction, temperature-programmed oxidation （TPO）, NH3 temperature-programmed desorption （NH3-TPD）, Fourier transform infrared spectroscopy （FT-IR）, and solid-state 31P magic angle spinning nuclear magnetic resonance （31P MAS NMR） were used for catalyst characterization. NH3-TPD results showed that both the acid quantity and strength of HZSM-5 were significantly changed after P modification. With increased P content, the density of strong acid sites decreased, while the weak acid sites changed little. TPO results indi-cated that catalyst deactivation was mainly caused by the deposition of coke. The catalyst with 5%P exhibited much better stability than the parent HZSM-5 due to the disappearance of strong acid sites after P modification. The FT-IR spectra of pyridine adsorption clearly revealed that with in-creased P content, there was an obvious decrease of Lewis acid sites and slight decrease of Br？nsted acid sites. From the results of 31P MAS NMR, NH3-TPD and FT-IR of adsorbed pyridine, a description of the effect of phosphorus modification on HZSM-5 was proposed.