(560gq) Structure-Property Relations of PtWOx/C Inverse Catalysts

Owing to the strong synergy between Pt and WO_x, the PtWO_x catalyst has been found to be efficient for a number of important reactions such as the oxidation of propane¹, ring-opening of tetrahydrofurfuryl alcohol² and hydrodeoxygenation of biomass derived compounds^3,4,5. Accumulated knowledge underscores that the close proximity of Pt and WO_x is crucial. However, catalysts prepared via conventional methods are heterogeneous in composition and particle size, rendering the establishment of structure-property relations difficult. Recently, atomic layer deposition (ALD) has been employed deposit a near monolayer of WO_x film on the surface of carbon-supported Pt. Comparing to the conventionally prepared PtWO_x catalysts, the inverse catalyst has demonstrated much higher efficiency for ring opening of tetrahydrofurfuryl alcohol.² It has been proposed that the partially reduced WO_x acts as a Brønsted acid that activates C-O bonds and stabilizes cationic intermediates.² However, the interaction between Pt and WO_x remains elusive. Structure-function correlations of the PtWO_x/C catalysts under working conditions are still lacking.

In this study, we use probe molecules, e.g., alcohols, to investigate the Brønsted acid sites on WO_x (@Pt) under different reaction environments and pretreatment conditions. Those probe molecules undergo acid-catalyzed elimination reactions and are sensitive to the configurational changes of PtWO_x catalyst during reaction. Combined strategies including kinetics, theoretical calculations as well as operando characterization reveal an intriguing interplay between Pt and WO_x.

References:

1. Wu, X. et al. Total Oxidation of Propane on Pt/WO_x/Al₂O₃ Catalysts by Formation of Metastable Pt¹⁺ Species Interacted with WO_x Clusters. J. Hazard. Mater. 225–226, 146–154 (2012).

2. Wang, C. et al. A Study of Tetrahydrofurfuryl Alcohol to 1,5-Pentanediol Over Pt-WO_x/C. Catal. Letters 148, 1047–1054 (2018).

3. Janampelli, S. & Darbha, S. Selective and Reusable Pt-WO_x/Al₂O₃ Catalyst for Deoxygenation of Fatty Acids and Their Esters to Diesel-range Hydrocarbons. Catal. Today 309, 219–226 (2018).

4. Wang, J. et al. Hydrogenolysis of Glycerol to 1,3-propanediol under Low Hydrogen Pressure over WO_x-Supported Single/Pseudo-Single Atom Pt Catalyst. 116023, 784–790 (2016).

5. Wang, C. et al. Mechanistic Study of the Direct Hydrodeoxygenation of m-Cresol over WO_x-Decorated Pt/C Catalysts. ACS Catal. 8, 7749–7759 (2018).