Modulating the dynamics of Brønsted acid sites on PtWO_x inverse catalyst

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 PtWO_x/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 PtWO_x/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.].