Nitrogen vacancy mediated exciton dissociation in carbon nitride nanosheets: Enhanced hydroxyl radicals generation for efficient photocatalytic degradation of organic pollutants

Polymeric materials are promising candidates as photocatalysts for environmental purification, however their catalytic performance are still unsatisfactory mainly due to the strong Coulomb interactions between electron and hole that leads to fast charge recombination. Herein, taking graphitic carbon nitride as an example, we verify that installing carbon nitride nanosheets with nitrogen vacancy could break the intrinsic electronic state distribution, forming energy disordered interfaces around the vacancies with the energy difference as large as 0.35 eV. Such a large energy difference is found energetic enough to overcome the strong Coulomb interactions between electron and hole for hot electron and hole generation, as a result showing high electron-hole separation efficiency. Benefited from these advantages, the as prepared material shows remarkable photocatalytic performance toward organic pollutants degradation. The improved catalytic performance is originated from the promoted exciton dissociation that leads to ultra high hydroxyl radical generation. This study offers a new understanding of the excitonic effects for designing advanced polymeric photocatalyst for energy and environment related applications.