BiVO4/P25 nanocomposites were synthesized using a modified citric acid complexing method. The photocatalytic activities of the nanocomposites were evaluated by the photodegradation of gaseous ethylene under visible light. The nanocomposites were characterized using X-ray powder diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, UV-visual diffuse reflectance spectroscopy, fluorescence spectrophotometry and field emission scanning electron microscopy. The results show that BiVO4/P25 nanocomposites presented multiphase nanosystem made of monoclinic, anatase and rutile phases. The addition of BiVO4 inhibited the growth of P25 grains (commercially nanometer titanium oxide) and the precipitation of the rutile phase. The light absorption of the nanocomposites was drastically extended to around 525 nm. n-N junction heterostructures were formed on the contact interface of the nanocomposites which enhanced the photocatalytic activity of the nanocomposites. Catalysts with a 3:1 BiVO4 to P25 mass ratio, denoted as 3M-BiVO4/P25, showed significantly higher photocatalytic activity than P25 or BiVO4. The degradation rate of ethylene was more than seven times that of P25 and over three times that of pure BiVO4. BiVO4/P25 nanocomposites also possessed good performance during catalyst reuse tests for the photocatalytic degradation of ethylene, which confirmed the stability and reusability of the composites. The photocatalytic mechanism at the n-N junctions in the heterostructure was discussed in detail as well. (C) 2016 Elsevier B.V. All rights reserved.