A full‐field PIV‐DIA technique has been coupled to concentration measurements in order to characterize the riser performance at different gas superficial velocities and reaction rates for ozone decomposition. Experiments under riser flow conditions were performed with the use of a compact pseudo‐2D lab‐scale riser reactor. The purpose of this work is to generate reliable experimental data to validate computational models for mass transfer in riser flow conditions. The catalytic activity of the particles was characterized. To analyze the reaction rate effect over the performance of a riser reactor, two catalyst batches with different activities were used and their kinetics were measured. The hydrodynamics of the gas‐solid flow was determined using the PIV‐DIA technique. Particle clusters were identified and characterized. By correlating the cluster information and mass concentration measurements, it was shown that a higher frequency of local flow heterogeneities near the walls led to higher conversion rates than in the core of the riser. Reaction rate and gas superficial effects are analyzed.