A new g-C3N4/SrTa2O6 heterojunction photocatalyst was designed and prepared by chimie douce (soft chemistry) method where carbon nitride (g-C3N4) was deposited over the metastable perovskite phase of SrTa2O6. The morphological study of the heterojunction using SEM and STEM revealed that g-C3N4 nanofibers are dispersed uniformly on the surface of SrTa2O6 plates leading to the intimate contact between them. The heterojunction could achieve a high and stable visible light photocatalytic H-2 generation of 137 mmol/h/mole of g-C3N4, which is much larger than the amount of hydrogen generated by one mole of pristine g-C3N4. A plausible mechanism for the observed enhanced photocatalytic activity for the heterojunction is proposed on the basis of effective charge separation of photogenerated electron-hole pairs, supported by band position calculations and photo-physical properties of g-C3N4 and srTa(2)O(6). (C) 2017 Elsevier B.V. All rights reserved.