第一作者简介: 武小满, 女, 博士, 副教授, 从事催化化学研究及教学工作。E- mail xm anw u77@ yahoo. com. cn[中文文摘]通过乙二醇液相还原法将少量金属Ru沉积在碳纳米管(简称CNTs)上,TEM、XRD表征结果表明,该法明显提高了Ru在CNTs上的分散度,Ru微晶的粒径在3~4 nm。氨分解反应结果表明,采用乙二醇液相还原法在降低Ru负载量的同时还明显提高了Ru/CNTs的催化氨分解活性。在0.4 MPa、773 K、空速GHSV100%NH3=30 000 mL/(h.g)反应条件下,在液相还原法制备的4.2%Ru/CNTs催化剂上氨分解转化率可达48.5%,约为同条件下浸渍法所得5%Ru/CNTs的1.3倍,液相还原最佳配比5.7%Ru/γ-Al2O3的1.2倍。表观活化能测试结果显示用CNTs代替γ-Al2O3作为载体或分散相并不引起所负载Ru催化剂上NH3分解制H2反应的表观活化能发生明显变化。[英文文摘]Nowadays catalytic decomposition of ammonia is regarded as a method to obtain COfree hydrogen for its application in proton exchange membrane fuel cell.In this paper,with carbon nano-tubes(as CNTs) as substrate,a series of metallic Ru/CNTs were prepared using glycol reduction-deposition method which enhanced markedly dispersion of Ru on CNTs with the Rux0-crystallite size at 3~4 nm characterized through TEM and XRD.Under reaction conditions of 0.4 MPa,773 K and GHSV100%NH3 = 30 000 mL/(h·g),the observed NH3- decomposition conversion over the 4.2% Ru/CNTs catalyst(prepared through ethylene-glycol reduction-deposition) reached 48.5%, which was about 1.2 times
as high as that of the 5.7% Ru /γ-Al2O3
catalyst prepared by the samemethod, and about 1.3 times as
high as that of the 5% Ru /CNTs catalyst prepared by conventional incip ientw etnessmethod. Over the 4%
Ru /CNTs catalys,t 100% o fNH3 - decomposition w as a ttained at 870 K; w hile over 5% Ru /CNTs prepared by conventional incipient wetness method, the reaction temperature as high as 900 K w as requ ired
for the same (100%) conversion. At 870 K, the observed NH3 - decomposit ion conversion w as only 81.
7% over the 5. 7% Ru /γ-Al2O3 catalys.t It was experimentally also found that using the CNTs in place of γ-Al2O3 as support of them etalRu- catalyst did not cause amarked change in the apparent activation
energy (Ea) for the reaction of NH3- decomposition to yieldH2.国家重点基础研究发展规划“973”项目(2005CB221400); 国家自然科学基金项目(20473063和20590364
