(Sr0.6Bi0.305)2Bi2O7/KNbO3 nanocomposites with significantly enhanced photocatalytic H2 generation driven by simulated sunlight

Abstract

A novel (Sr0.6Bi0.305)2Bi2O7/KNbO3 Z-scheme heterojunction was synthesized by two-step hydrothermal method and its photocatalytic activity for splitting water was studied under simulated sunlight. Compared with KNbO3 and (Sr0.6Bi0.305)2Bi2O7, the as-prepared (Sr0.6Bi0.305)2Bi2O7/KNbO3 samples exhibited remarkably enhanced photocatalytic activity for H2 production. It was found that the H2 production efficiency of (Sr0.6Bi0.305)2Bi2O7/KNbO3 (1:800) composite was nearly 39.5 times as large as that of pure KNbO3. The potential fields at interfaces between KNbO3 and (Sr0.6Bi0.305)2Bi2O7 with different energy band potential can drive the secondary distribution of photogenerated carriers, thereby improving photocatalytic activity. The composite demonstrates good stability for photocatalytic activities and still has excellent H2 production performance after four cycle experiments. This work verifies that the addition of a small amount of (Sr0.6Bi0.305)2Bi2O7 into the photocatalytically H2-generating semiconducting materials is an efficient strategy for significantly boosting photocatalytic H2 evolution.