At the industrial level, Ag catalysts in the form of silver crystals held by a silver gauze are largely used for formaldehyde production and ethylene epoxidation. These self-supported structures undergo surface reconstructions and morphological changes upon exposure to moderately high temperatures (473–900 K) and oxidising atmospheres. These phenomena have been studied and well understood on single crystal surfaces and polycrystalline foils: different oxygen surface and sub-surface species have been identified and reconstruction processes explained. To verify the scalability of the surface science results and ultimately understand these phenomena on catalysts at the industrial scale, further studies on more complex samples are needed. Attempts to close this “materials gap” have been carried out in this present study where experiments have been performed on model single catalytic nanoparticles, i.e. the apexes of field emitter tips, using both field emission (FE) and field ion (FI) microscopies. Pure Ag samples are exposed to a pressure of 3 × 10^–5 mbar of O₂ at temperatures up to 700 K. These conditions reflect those used on the industrial scale. Important surface/morphological reconstructions are observed both in FE and FI modes. For comparison, experiments have been repeated on Au-8.8%at. Ag field emitter tips, representative samples for Au–Ag catalytic nanofoams, using to 3 × 10^–5 mbar of NO₂ at temperatures up to 450 K. Similar behaviour are observed and the influence of the oxidising gas is discussed.

在工业水平上，由银丝网保持的银晶体形式的Ag催化剂主要用于甲醛生产和乙烯环氧化。这些自支撑结构在暴露于中等高温（473–900 K）和氧化性气氛后会经历表面重建和形态变化。这些现象已经在单晶表面和多晶箔上进行了研究并得到了很好的理解：已经确定了不同的氧表面和亚表面物种，并解释了重建过程。为了验证表面科学结果的可扩展性并最终了解工业规模的催化剂上的这些现象，需要对更复杂的样品进行进一步的研究。在本研究中已经进行了试图缩小“材料间隙”的尝试，其中使用场发射（FE）和场离子（FI）显微镜对单催化纳米颗粒模型（即场发射器尖端的顶点）进行了实验。纯银样品暴露在3×10的压力下最高700 K的温度下^–5  mbar O _2。这些条件反映了工业规模上使用的条件。在FE和FI模式下均观察到重要的表面/形态重建。为了比较，在Au-8.8％at上重复实验。Ag场发射器尖端，Au-Ag催化纳米泡沫的代表性样品，在高达450 K的温度下使用3×10 ^–5  mbar的NO _2。观察到类似的行为，并讨论了氧化气体的影响。