Enhanced visible light photocatalytic water reduction from a g-C3N4/SrTa2O6 heterojunction

Abstract A new g-C 3 N 4 /SrTa 2 O 6 heterojunction photocatalyst was designed and prepared by chimie douce (soft chemistry) method where carbon nitride (g-C 3 N 4 ) was deposited over the metastable perovskite phase of SrTa 2 O 6 . The morphological study of the heterojunction using SEM and STEM revealed that g-C 3 N 4 nanofibers are dispersed uniformly on the surface of SrTa 2 O 6 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-C 3 N 4 , which is much larger than the amount of hydrogen generated by one mole of pristine g-C 3 N 4 . 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-C 3 N 4 and SrTa 2 O 6 .