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 (lambda > 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 H-2 evolution rate is 5.8, 2.1, 2.2 time higher than that of CN. CNI, CNI-R, respectively. And its photocatalytic CH, 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 CM. 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. (C) 2020 Elsevier B.V. All rights reserved.