Photoredox catalysis uses visible light to drive single-electron transfer reactions that are otherwise thermally inaccessible.
hv + Cat -> Cat*
Cat* + S -> Cat+ + S(-) -> P
TOF ~ I_light * [Cat]
- Substrate feed — photoactive substrate molecules pumped continuously through the illuminated reactor coil.
- Catalyst sites — photocatalyst molecules (e.g. Ru/Ir complexes) fixed along the transparent tubing wall.
- Light intensity — LED irradiance striking the flow cell; higher intensity excites more catalyst per second.
- Flow turnover — how fast a bound intermediate releases product and frees the catalyst for another cycle.
Continuous-flow photoredox reactors are used industrially to scale up pharmaceutical intermediate synthesis without the poor light penetration that plagues large batch photoreactors.