摘要
采用KBH4液相还原法制备了系列活性炭(AC)负载的Pt-M(M=Fe,Ni,Co,Zn,Cu)双金属催化剂,考察了该系列催化剂对甘油水溶液原位加氢制备1,2-丙二醇反应的催化性能.结果表明,当Pt负载量(质量分数)为2.0%,Pt/Ni质量比为1∶1时,在220℃和1.0 MPa氮气压力下反应8 h,2%Pt-2%Ni/AC催化剂上甘油转化率和1,2-丙二醇选择性分别达到98.7%和60.5%;且在5次重复使用过程中,催化剂保持较高的稳定性.采用氮气物理吸附-脱附实验、X射线衍射(XRD)、透射电子显微镜(TEM)、选区电子衍射(SAED)及X射线光电子能谱(XPS)等对催化剂的结构和形貌进行了表征.结果表明,粒径约为2 nm的纳米颗粒在活性炭载体上均匀分散,纳米粒子中金属多以还原态形式存在,Ni原子进入Pt晶格中形成的Pt-Ni物种使Pt与Ni之间表现出强相互作用力.通过比较Pt/AC,Ni/AC与Pt-Ni/AC双金属催化剂的催化性能,推断Pt能够促进甘油水溶液重整而Ni有利于氢解反应,Pt-Ni金属间协同作用是Pt-Ni/AC催化剂对甘油原位加氢反应具有优良催化性能的重要原因.
A series of activated carbon supported Pt-M（ M = Fe,Ni,Co,Zn,Cu） bimetallic catalysts was prepared via KBH4 reduction method for glycerol in situ hydrogenolysis to produce 1,2-propanediol. The results showed that Pt-Ni / AC catalyst with a Pt loading（ mass fraction） of 2. 0% and a Pt / Ni mass ratio of 1 ∶ 1 displayed excellent performance at 220 ℃ under 1. 0 MPa of N_2 after 8 h reaction time,with a high selectivity of60. 5% and a conversion of 98. 7%. In addition,the prepared Pt-Ni / AC had a good catalytic stability,which kept a high activity even after five cycles catalytic evaluation. The results from the characterization of catalysts by N_2 physisorption,XRD,TEM and XPS indicated that nanoparticles with an average size of ca. 2 nm were uniformly dispersed on the support. And the majority of metals in nanoparticles are present in the zerovalent metallic state. The formation of Pt-Ni phase due to the incorporation of Ni in the Pt lattice was responsible for the strong interaction between Pt and Ni metal. The catalytic performance of Pt-Ni / AC was compared with that of Pt / AC and Ni / AC,it was clearly observed that Pt could promote the aqueous phase reforming of glycerol to hydrogen,and Ni could facilitate the hydrogenolysis of glycerol. The unique perfor-mance of Pt-Ni / AC bimetallic catalysts was attribute to the the synergistic effect between Pt and Ni.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2016年第6期1140-1147,共8页
Chemical Journal of Chinese Universities
基金
国家自然科学基金(批准号:21376083)资助~~
关键词
甘油水溶液
原位加氢
双金属催化剂
液相还原
1
2-丙二醇
Glycerol aqueous solution
In situ hydrogenolysis
Bimetallic catalyst
Liquid phase reduction
1
2-Propanediol
