Methyl steric–hindrance–induced twisted acridine–based conjugated porous polymers for efficient 1O2–driven photocatalytic H2O2 production

These lead to an accumulation of triplet excitons and dominant 1O2 generation through energy transfer. The electrophilic 1O2 possesses a lower adsorption energy barrier on the photocatalyst surface, favoring subsequent proton–coupled electron transfer reactions. Consequently, 1O2–dominated CPP–G exhibits a remarkable H2O2 production rate of 8.97 mmol g-1 h-1 in pure water without sacrificial agents, significantly outperforming the O2•-–dominated CPP–A (5.13 mmol g-1 h-1).

Furthermore, CPP–G demonstrates high efficiency and selectivity in 1O2–mediated organic transformations. This work demonstrates that steric hindrance engineering serves as a generalizable strategy, enabling a fundamental shift in the reactive oxygen species generation pathway, from charge transfer to energy transfer, via simple structural modifications in metal–free CPP photocatalytic systems.