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首页> 外文期刊>Langmuir: The ACS Journal of Surfaces and Colloids >Pt_3Ti nanoparticles: Fine dispersion on SiO_2 supports, enhanced catalytic CO oxidation, and chemical stability at elevated temperatures
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Pt_3Ti nanoparticles: Fine dispersion on SiO_2 supports, enhanced catalytic CO oxidation, and chemical stability at elevated temperatures

机译：Pt_3Ti纳米粒子：在SiO_2载体上的精细分散，增强的催化CO氧化以及在高温下的化学稳定性

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摘要

A platinum-based intermetallic phase with an early d-metal, Pt _3Ti, has been synthesized in the form of nanoparticles (NPs) dispersed on silica (SiO_2) supports. The organometallic Pt and Ti precursors, Pt(1,5-cyclooctadiene)Cl_2 and TiCl _4(tetrahydrofuran)_2, were mixed with SiO_2 and reduced by sodium naphthalide in tetrahydrofuran. Stoichiometric Pt _3Ti NPs with an average particle size of 2.5 nm were formed on SiO_2 (particle size: 20-200 nm) with an atomically disordered FCC-type structure (Fm3?m; a = 0.39 nm). A high dispersivity of Pt _3Ti NPs was achieved by adding excessive amounts of SiO_2 relative to the Pt precursor. A 50-fold excess of SiO_2 resulted in finely dispersed, SiO_2-supported Pt_3Ti NPs that contained 0.5 wt % Pt. The SiO_2-supported Pt_3Ti NPs showed a lower onset temperature of catalysis by 75 °C toward the oxidation reaction of CO than did SiO_2-supported pure Pt NPs with the same particle size and Pt fraction, 0.5 wt %. The SiO_2-supported Pt_3Ti NPs also showed higher CO conversion than SiO_2-supported pure Pt NPs even containing a 2-fold higher weight fraction of Pt. The SiO_2-supported Pt_3Ti NPs retained their stoichiometric composition after catalytic oxidation of CO at elevated temperatures, 325 °C. Pt_3Ti NPs show promise as a catalytic center of purification catalysts for automobile exhaust due to their high catalytic activity toward CO oxidation with a low content of precious metals.
机译：已以分散在二氧化硅（SiO_2）载体上的纳米颗粒（NPs）形式合成了具有早期d-金属的铂基金属间相Pt _3Ti。将有机金属Pt和Ti前体Pt（1,5-环辛二烯）Cl_2和TiCl_4（四氢呋喃）_2与SiO_2混合，并在四氢呋喃中用萘钠还原。在具有原子无序的FCC型结构（Fm3≤m; a ＝ 0.39nm）的SiO_2（粒径：20-200nm）上形成平均粒径为2.5nm的化学计量的Pt_3Ti NP。通过添加相对于Pt前驱体过量的SiO_2，可以实现Pt _3Ti NPs的高分散性。过量的50倍的SiO_2产生了细分散的，SiO_2负载的Pt_3Ti NP，其中包含0.5 wt％的Pt。 SiO_2负载的Pt_3Ti NPs对CO的氧化反应的催化起始温度低75°C，而SiO_2负载的纯Pt NPs的粒径和Pt分数相同，为0.5 wt％。 SiO_2负载的Pt_3Ti NPs也比SiO_2负载的纯Pt NPs表现出更高的CO转化率，即使Pt的重量分数高2倍。 SiO_2负载的Pt_3Ti NP在325°C的高温下催化氧化CO后仍保持其化学计量组成。 Pt_3Ti NPs因其对CO氧化的催化活性高，贵金属含量低而显示出有望作为汽车尾气净化催化剂的催化中心。

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