Kumar Naresh, Kalirai Sam, Wain Andrew J, Weckhuysen Bert M
Inorganic Chemistry and Catalysis Group Debye Institute for Nanomaterials Science Utrecht University Universiteitsweg 99 Utrecht 3584 CG The Netherlands.
National Physical Laboratory Hampton Road Teddington, TW11 0LW United Kingdom.
ChemCatChem. 2019 Jan 9;11(1):417-423. doi: 10.1002/cctc.201801023. Epub 2018 Jul 31.
Determining the active site in real-life solid catalysts remains an intellectual challenge and is crucial for exploring the road towards their rational design. In recent years various micro-spectroscopic methods have revealed valuable structure-activity data at the level of a single catalyst particle, even under reaction conditions. Herein, we introduce Tip-Enhanced FLuorescence (TEFL) microscopy as a novel and versatile characterization tool for catalysis research. This has been achieved using a Fluid Catalytic Cracking (FCC) catalyst as showcase material. Thin sectioning of industrially used FCC particles together with selective staining of Brønsted acidity has enabled high-resolution TEFL mapping of different catalyst regions. Hyperspectral information gained via TEFL microscopy reveals a spatial distribution of Brønsted acidity within individual zeolite domains in different regions of the FCC catalyst particle. Comparison of TEFL measurements from different FCC particles showed significant intra- and inter-particle heterogeneities both in zeolite domain size and chemical reactivity.
确定实际应用中的固体催化剂的活性位点仍然是一项智力挑战，对于探索合理设计催化剂的道路至关重要。近年来，各种微光谱方法已经揭示了在单个催化剂颗粒水平上，甚至在反应条件下的有价值的结构-活性数据。在此，我们引入针尖增强荧光（TEFL）显微镜作为催化研究的一种新型通用表征工具。这是通过使用流化催化裂化（FCC）催化剂作为展示材料来实现的。对工业用FCC颗粒进行薄片切片，并对布朗斯台德酸度进行选择性染色，从而实现了对不同催化剂区域的高分辨率TEFL映射。通过TEFL显微镜获得的高光谱信息揭示了FCC催化剂颗粒不同区域中单个沸石域内布朗斯台德酸度的空间分布。对不同FCC颗粒的TEFL测量结果进行比较表明，在沸石域大小和化学反应性方面，颗粒内部和颗粒之间均存在显著的不均匀性。
