Abstract
Brønsted acid sites on the oxide overlayers of metal–metal oxide inverse catalysts are often hypothesized to drive selective C–O bond activation. However, the Brønsted acid site nature and dynamics under working conditions remain poorly understood due to the functionalities of the constituent materials. Here we investigate the formation and the dynamics of Brønsted acid and redox sites on PtWOx/C under working conditions. Density functional theory-based thermodynamic calculations and microkinetic modelling reveal a complex interplay between Brønsted acid and redox sites and potentially fast catalyst dynamics at comparable timescales to the Brønsted acid catalysed dehydration chemistry. Combining in situ characterization and probe chemistry, we demonstrate that the density of Brønsted acid sites on the PtWOx/C inverse catalyst could be modulated by up to two orders of magnitude by altering the reaction parameters and by the chemistry itself. We elicit an order of magnitude increase in the acid-catalysed dehydration average reaction rate by periodic hydrogen pulsing. [Figure not available: see fulltext.].
| Original language | English |
|---|---|
| Pages (from-to) | 144-153 |
| Number of pages | 10 |
| Journal | Nature Catalysis |
| Volume | 5 |
| Issue number | 2 |
| DOIs | |
| State | Published - Feb 2022 |
| Externally published | Yes |
Funding
This work was financially supported primarily by the Catalysis Center for Energy Innovation, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences under award number DESC0001004. Portions of this work were performed at the DuPont–Northwestern–Dow Collaborative Access Team (DND-CAT) located at Sector 5 of the Advanced Photon Source. DND-CAT is supported by Northwestern University, E.I. DuPont de Nemours and Co. and The Dow Chemical Company. This research used resources of the Advanced Photon Source, a US Department of Energy, Office of Science user facility operated for the Department of Energy, Office of Science by Argonne National Laboratory under contract no. DE-AC02-06CH11357. The research was carried out in part at the 7-BM (QAS) beamline of the National Synchrotron Light Source II at Brookhaven National Laboratory, which is supported by the Synchrotron Catalysis Consortium, US Department of Energy under grant no. DE-SC0012335 and at the Center for Functional Nanomaterials, Brookhaven National Laboratory, which is supported by the US Department of Energy, Office of Basic Energy Sciences under contract no. DE-SC0012704. Some of the XPS measurements were carried out using the Thermo Scientific K-Alpha+ XPS System at the University of Delaware surface analysis facility supported by NSF (no. 1428149). Y.L. acknowledges financial support from the Chinese Academy of Science Youth Innovation Promotion Association (no. 2018220) and LiaoNing Revitalization Talents Program (no. XLYC1907053), and X.L. acknowledges financial support from the National Natural Science Foundation of China (nos. 21872163, 22072090, 21991153 and 21991150) for the annular dark-field (ADF)-STEM analysis. The authors acknowledge H. Matsumoto for assistance with STEM data acquisition from a Hitachi HF5000 microscope. We acknowledge W. Wu for assisting with the XPS measurements, Q. Ma, S. Ehrlich, N. S. Marinkovic and L. Ma for helping with the XAS measurements and S. Prodinger for valuable discussions.