Albinsson David, Bartling Stephan, Nilsson Sara, Ström Henrik, Fritzsche Joachim, Langhammer Christoph
Department of Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
Department of Mechanics and Maritime Sciences, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
Sci Adv. 2020 Jun 19;6(25):eaba7678. doi: 10.1126/sciadv.aba7678. eCollection 2020 Jun.
Nanoconfinement in porous catalysts may induce reactant concentration gradients inside the pores due to local conversion. This leads to inefficient active material use since parts of the catalyst may be trapped in an inactive state. Experimentally, these effects remain unstudied due to material complexity and required high spatial resolution. Here, we have nanofabricated quasi-two-dimensional mimics of porous catalysts, which combine the traits of nanofluidics with single particle plasmonics and online mass spectrometry readout. Enabled by single particle resolution at conditions during CO oxidation over a Cu model catalyst, we directly visualize reactant concentration gradient formation due to conversion on single Cu nanoparticles inside the "model pore" and how it dynamically controls oxidation state-and, thus, activity-of particles downstream. Our results provide a general framework for single particle catalysis in the gas phase and highlight the importance of single particle approaches for the understanding of complex catalyst materials.
多孔催化剂中的纳米限域效应可能会因局部转化而在孔内引发反应物浓度梯度。这会导致活性材料利用效率低下，因为部分催化剂可能会被困在非活性状态。在实验中，由于材料的复杂性和所需的高空间分辨率，这些效应尚未得到研究。在此，我们通过纳米制造技术制备了多孔催化剂的准二维模拟物，它将纳米流体学的特性与单粒子等离子体激元以及在线质谱读出相结合。在铜模型催化剂上进行一氧化碳氧化反应的条件下，借助单粒子分辨率，我们直接观察到了“模型孔”内单个铜纳米颗粒上由于转化而形成的反应物浓度梯度，以及它如何动态地控制下游颗粒的氧化态——进而控制其活性。我们的研究结果为气相中的单粒子催化提供了一个通用框架，并突出了单粒子方法对于理解复杂催化剂材料的重要性。
