Constitutional isomerism in conjugated covalent organic polymers for photocatalytic H2O2 production.

A pair of isomeric covalent organic polymers were developed for visible-light-driven H2O2 production. Although COP-1 and COP-2 possess similar chemical compositions, their distinct constitutional arrangements lead to markedly different porosity, band structures and charge-transfer behaviours. As a result, COP-2 achieves an H2O2 production rate of 3629 µmol g-1 h-1, substantially outperforming COP-1. Mechanistic studies reveal that the enhanced activity mainly originates from promoted O2 activation and a favorable two-electron oxygen reduction pathway. These results highlight how isomeric connectivity can modulate the physicochemical properties and H2O2 photosynthesis performance of conjugated polymer photocatalysts.