Centre for Catalysis Research and c*change (DST-NRF Centre of Excellence in Catalysis), Department of Chemical Engineering, University of Cape Town, Cape Town (South Africa).
Angew Chem Int Ed Engl. 2014 Jan 27;53(5):1342-5. doi: 10.1002/anie.201306899. Epub 2014 Jan 21.
The utilization of metal nanoparticles traverses across disciplines and we continue to explore the intrinsic size-dependent properties that make them so unique. Ideal nanoparticle formulation to improve a process's efficiency is classically presented as exposing a greater surface area to volume ratio through decreasing the nanoparticle size. Although, the physiochemical characteristics of the nanoparticles, such as phase, structure, or behavior, may be influenced by the nature of the environment in which the nanoparticles are subjected1, 2 and, in some cases, could potentially lead to unwanted side effects. The degree of this influence on the particle properties can be size-dependent, which is seldom highlighted in research. Herein we reveal such an effect in an industrially valuable cobalt Fischer-Tropsch synthesis (FTS) catalyst using novel in situ characterization. We expose a direct correlation that exists between the cobalt nanoparticle's size and a phase transformation, which ultimately leads to catalyst deactivation.
金属纳米粒子的应用跨越了多个学科领域，我们一直在探索其内在的尺寸依赖性特性，这些特性使它们如此独特。通过减小纳米粒子的尺寸来提高过程效率的理想纳米粒子配方，经典地表现为暴露更大的表面积与体积比。然而，纳米粒子的物理化学特性，如相、结构或行为，可能受到纳米粒子所处环境的性质的影响 1,2，在某些情况下，可能会导致不必要的副作用。这种对颗粒性质的影响程度可能是尺寸依赖性的，这在研究中很少被强调。在这里，我们使用新颖的原位表征方法揭示了在一种具有工业价值的钴费托合成 (FTS) 催化剂中存在的这种影响。我们揭示了钴纳米粒子的尺寸与其相转变之间存在直接的相关性，这最终导致了催化剂失活。
