Preparation of alumina-supported intermetallic compounds
Preparation of alumina-supported intermetallic compounds
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DOI：
10.1039/c3ra43163k
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发表时间：
2013-01-01
期刊：
影响因子：
3.9
通讯作者：
Komatsu, Takayuki
中科院分区：
文献类型：
--
作者：
Furukawa, Shinya;Ozawa, Kenichi;Komatsu, Takayuki
以γ-Al_2O_3为载体，通过还原两种金属前驱体制备了一系列具有应用前景的金属间化合物：Pt_3Co/Al_2O_3、PtCu/Al_2O_3、Pt_3Sn/Al_2O_3和Pd_3Pb/Al_2O_3。作为Pt前体，使用与第二金属前体偶联的[Pt（NH3）（4）]（2+）或PtCl 62-。两种不同的还原程序，气态H-2和LiBH 4在液相中，也被采用和比较。使用具有比[Pt（NH3）（4）]（2+）更负的还原电势的PtCl 62-强烈增强了所需Pt基金属间纳米颗粒的形成，而与还原过程无关。与Pd 2+相比，在Pd 3 Pb/Al 2 O3的制备中观察到类似的趋势。强还原剂LiBH 4在所有情况下都比H-2得到更高含量的相应金属间相。采用氯化物配合物和LiBH 4还原法制备了单相金属间化合物。系统的研究表明，金属间化合物形成的程度本质上取决于两种金属前体的还原电位差（Δ E）。具有小Δ E的双金属组合如PdCl_（42-）/Bi_（3+）、Co_（2+）/SnCl_（62-）和Ni_（2+）/SnCl_（62-）也允许通过H-2还原分别合成PdBi/Al_2 O_3、Co_3Sn_2/Al_2 O_3、Ni_3Sn_2/Al_2 O_3和Ni_3Sn_2/Al_2 O_3。选择合适的金属前驱体来降低DE是合成氧化铝负载金属间化合物的有效策略。
A series of alumina-supported intermetallic compounds, Pt3Co/Al2O3, PtCu/Al2O3, Pt3Sn/Al2O3 and Pd3Pb/Al2O3, being promising materials as catalysts, were prepared by reduction of two metal precursors co-impregnated on gamma-Al2O3. As a Pt precursor, [Pt(NH3)(4)](2+) or PtCl62- was used coupled with the second metal precursors. Two different reduction procedures, gaseous H-2 and LiBH4 in liquid phase, were also employed and compared. Using PtCl62- which possesses a more negative reduction potential than [Pt(NH3)(4)](2+) strongly enhanced formation of the desired Pt-based intermetallic nanoparticles regardless of the reduction procedure. A similar trend was observed in preparation of Pd3Pb/Al2O3 with PdCl42- compared to Pd2+. A strong reduction agent LiBH4 gave higher contents of the corresponding intermetallic phases than H-2 in all cases. Single-phase intermetallic compounds supported on alumina were synthesized by employing the chloro-complexes and LiBH4 reduction. A systematic investigation indicates that the degree of intermetallic formation intrinsically depends on the difference in reduction potentials (Delta E) of the two metal precursors. Bimetallic combinations with small Delta E such as PdCl42-/Bi3+, Co2+/SnCl62- and Ni2+/SnCl62- also allow syntheses of PdBi/Al2O3, Co3Sn2/Al2O3, Ni3Sn/Al2O3 and Ni3Sn2/Al2O3 by H-2 reduction, respectively. An appropriate choice of the metal precursor to reduce DE is an effective strategy to synthesize an alumina-supported intermetallic compound.