Synergy of nitrogen vacancies and intercalation of carbon species for enhancing sunlight photocatalytic hydrogen production of carbon nitride

Enhancing the separation of photogenerated electrons and holes is crucial for improving the photocatalytic performance of carbon nitride (CN). In this work, a ECN-VN/C photocatalyst with unique three-dimensional nanostructure was constructed by exfoliation of multilayered CN, followed by introduction of nitrogen vacancies and intercalation of carbon species between the exfoliated CN nanosheets. Compared to pristine CN, ECN-VN/C photocatalyst has stronger light absorption, more surface active sites, and better separation efficiency of photogenerated carriers. Formation of dual built-in electric fields in ECN-VN/C, which result from the synergy of nitrogen vacancies and intercalation of carbon species, promotes the migration of photogenerated electrons and holes in opposite directions, and greatly accelerates the separation efficiency of these carriers. Photocatalytic hydrogen production activity of ECN-VN/C photocatalyst was 12.1 times higher than that of pristine CN. The synergy between nitrogen vacancies and intercalation of carbon species provides a new strategy for designing more efficient CN-based photocatalysts.