Generally, the characteristics of the inserts play a major role for the photocatalytic performance. It is notable that the performance of the photocatalytic system is not solely dependent on the photocatalyst loading, which is the most obvious parameter. The design of the inserts also plays a significant role in influencing the performance of the system. This influence is not merely related to a change in the absolute irradiated surface area and the amount of photocatalysts, but also extends to other aspects such as the hydrodynamic conditions within the insert. The observed positive effect of pulsed irradiation is particular interesting as it gives evidence that an optimization of the irradiation conditions holds potential to increase the overall efficiency of the photocatalytic reduction of nirobenzene. A further exploitation of this effect requires an optimization of the intensity, the pulse frequency and the duty cycle to achieve high reaction rates together with high photonic efficiencies.