A modular design approach to allow the identification of photoactive structures in solid molecular catalysts

Efficient utilization of solar energy remains paramount in the context of a more sustainable future. To enable rational design of heterogeneous photocatalysts, a deeper understanding of photoactive structures and reaction mechanisms is required. In this study, a modular semiconductor design platform along the axes of pyridine denticity and an amine functionalization is presented. In the model, photocatalytic hydrogen peroxide production, the best-performing catalyst achieves productivities upwards of 2.3 mmol mmol h-1 g-1 under white light irradiation at 500 W m-2. Through application as a coating, both apparent quantum yields (1.27%) and solar-to-chemical conversion efficiencies (0.28%) were significantly improved. In radical scavenging experiments, the modular design approach allows the correlation of catalyst structures with the formation of different radical species, and in turn, mechanistic pathways. On the basis of this knowledge, the decomposition of waste organics is identified and demonstrated as suitable use-case. This work provides a template for the informed design of photocatalysts and the characterization of the underlying reaction mechanisms.