Since, the light penetration decreases with an increasing catalyst concentration, simply increasing this parameter will not necessarily lead to improved kinetics. We wanted to investigate if with more effective mixing, higher catalyst concentrations would be within reach, therefore offering the potential to boost the productivity. However, as can be observed in the results in Fig 5 ; this was not the case. Either due to the issue of transmittance or the limitation of the photon flux, the yield was not boosted by doubling catalyst concentration.