Monitoring mass transport in heterogeneously catalyzed reactions by field-gradient NMR for assessing reaction efficiency in a single pellet

►Catalytic gas-liquid reaction is monitored via effective diffusion coefficients. ► Field-gradient NMR is used to determine displacement statistics of fluid molecules. ► Gas bubbles forming reaction is used as model reaction. ► Can be implemented in exothermic reactions with significant convective mass transport. ► Potential to become a routine tool with high-field and low-field devices.