CN/iodine-doped CN homojunction powder catalysts with excellent visible-light photocatalytic properties

Abstract Although carbon nitride (CN) catalyst has great attraction, the relatively low separation efficiency of photogenerated carriers leads to its unsatisfactory photocatalytic performance. Herein, CN/iodine-doped CN (CN/CNI) homojunction powder catalysts were fabricated via a facile water-bath combined with in-situ sintering method. The optimized CN/CNI-40% catalyst with a proper CN content shows prominent visible-light (λ > 420 nm) photocatalytic performance and stability. Its photocatalytic conversion ratio for Rhodamine B (RhB) is 5.1, 2.7, 3.0 time higher than that of CN, CNI and CNI-R (reference sample), respectively. Its photocatalytic H2 evolution rate is 5.8, 2.1, 2.2 time higher than that of CN, CNI, CNI-R, respectively. And its photocatalytic CH4 generation rate is 4.9, 3.5, 3.6 time higher than that of CN, CNI, CNI-R, respectively. This remarkably improved activity was mainly caused by the synergistic effect of CN and CNI, which can contribute to the excellent absorption performance in the 442–591 nm regions and the efficient separation of photoinduced electron-hole pairs provided by the well-matched band structures and homojunction interfaces between CN and CNI. The probable mechanism of remarkably improved photocatalytic property was also investigated. This study offers a novel and rational avenue to synthesize cheap and high-efficiency multifunctional photocatalysts applied in environmental and energy fields.