Localized thermal levering events drive spontaneous kinetic oscillations during CO oxidation on Rh/Al2O3

Abstract

Unravelling kinetic oscillations, which arise spontaneously during catalysis, has been a challenge for decades but is important not only to understand these complex phenomena but also to achieve increased activity. Here we show, through temporally and spatially resolved operando analysis, that CO oxidation over Rh/Al2O3 involves a series of thermal levering events—CO oxidation, Boudouard reaction and carbon combustion—that drive oscillatory CO2 formation. This catalytic sequence relies on harnessing localized temperature episodes at the nanoparticle level as an efficient means to drive reactions in situations in which the macroscopic conditions are unfavourable for catalysis. This insight provides a new basis for coupling thermal events at the nanoscale for efficient harvesting of energy and enhanced catalyst technologies. Understanding oscillation phenomena in catalysis is a long-standing challenge. Here the authors report a temporally and spatially resolved operando analysis of CO oxidation over Rh/Al2O3, revealing the interplay of Boudouard reaction and carbon combustion in generating the oscillations.