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纳米金的催化性能受载体影响巨大,选择合适的载体或设计金属—载体界面精细结构能显著影响纳米金的催化性能.迄今发现各种载体包括酸、碱金属氧化物、碳材料以及有机聚合物均可作为纳米金的有效载体.相应的各种金催化剂均展现出独特的催化活性与选择性.一个典型的例子是核壳结构的Au/NiO催化剂,基于该催化剂催化异丁烯醛制备异丁烯酸甲酯的化工厂已于2008年开始兴建.金催化剂在AsH_3气体传感器和汞收集器等环境分析方面也开始实际应用.因而,金催化剂的稳定性和使用寿命成为当前关注的焦点问题.目前报道的长寿命金催化剂典型例子有MINTEK催化剂和YD-3烟台催化剂,后者是由α-Fe2O3和La2O3改性氧化铝负载的金催化剂.中国科学院大连化学物理研究所张涛院士和王军虎研究员团队在近期研究中发现高温焙烧条件下Au纳米颗粒与羟基磷灰石(HAP)载体之间会发生金属-载体强相互作用(Strong Metal-Support Interaction简称SMSI)效应.SMSI效应导致载体对Au纳米颗粒形成包裹,可以有效提升Au纳米颗粒的抗烧结性能,但其对活性位的覆盖也会导致催化剂活性的下降.最近,该团队通过向载体HAP中添加Ti O2进行修饰,成功设计开发出Au/HAP-Ti O2催化剂.该催化剂上Au纳米颗粒与HAP接触的一侧被HAP薄层包裹,与Ti O2接触的一侧裸露,呈现出独特的半包裹结构.通过这种纳米尺度的结构设计,该金催化剂经过800°C的高温焙烧后不仅对一系列反应均表现出可观的催化活性和优异的抗烧结性能,且在模拟汽车尾气CO消除反应中表现出优于商业三效催化剂的反应稳定性.该工作为负载型纳米金催化剂的应用,特别是在高温催化反应中的实际应用提供了新途径,因此有望促进负载型金催化剂的实用化乃至商业化进程.
The catalytic performance of nano-gold is greatly affected by the carrier, and selecting the appropriate carrier or designing the fine structure of the metal-carrier interface can significantly affect the catalytic performance of the nano-gold. Various supports have been found to include acid, alkali metal oxides, carbon materials and organic polymers Can be used as an effective carrier of gold nanoparticles.All the corresponding gold catalysts have shown a unique catalytic activity and selectivity.A typical example is the core-shell Au / NiO catalyst, based on the catalyst for methacrolein preparation of methyl methacrylate Ester chemical plant was started construction in 2008. The gold catalyst has also started to be applied in environmental analysis such as AsH 3 gas sensor and mercury collector etc. Therefore, the stability and service life of the gold catalyst have become the current focus issues. Typical examples of long-lived gold catalysts include MINTEK catalyst and YD-3 Yantai catalyst, which is a gold catalyst supported by α-Fe2O3 and La2O3 modified alumina. Recently, a team of researchers Zhang Tao and Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Au nanoparticles and hydroxyapatite (HAP) carriers were found under high temperature calcination conditions A strong Metal-Support Interaction (SMSI) effect may occur.SMSI effect causes the carrier to form Au nanoparticles and effectively enhances the anti-sinterability of the Au nanoparticles, but the coverage of the active sites Resulting in a decrease in catalyst activity.The team recently successfully designed and developed the Au / HAP-Ti O2 catalyst by adding Ti O2 to the support HAP.The Au nanoparticles on the catalyst were coated with HAP on one side that was in contact with HAP , The side exposed to Ti O2 is exposed, showing a unique semi-parcel structure through this nano-scale structure design, the gold catalyst calcined at a high temperature of 800 ° C not only shows a considerable catalytic activity for a series of reactions And excellent sintering resistance, and showed better reaction stability than the commercial three-way catalyst in the simulation of automobile exhaust CO elimination reaction.This work is the application of supported nano gold catalyst, especially in the high temperature catalytic reaction Provides a new way, it is expected to promote the commercialization of supported gold catalysts and even the commercialization process.