Novel inverse opal Bi2WO6/Bi2O3 S-scheme heterojunction with efficient charge separation and fast migration for high activity photocatalysis

For enhancing the photocatalytic performance, efficient separation and rapid migration of photogenerated charge carriers are essential. This study adopted a hydrothermal technique followed by calcination to remove the template to prepare a novel IOBi2WO6/Bi2O3 S-scheme heterojunction with a distinctive inverse opal (IO) structure. Under simulated solar irradiation, the obtained IOBi2WO6/Bi2O3 heterojunction demonstrated improved photocatalytic performance toward photocatalytic hydrogen (H2) evolution. Among all the samples, the IOBi2WO6/15Bi2O3 possessed the highest photocatalytic H2 evolution activity and reached up to 312.56 mol g-1h−1, which was 9.7 and 3.4 times higher than that of the pristine Bi2WO6 (32.15 mol g-1h−1) and IOBi2WO6 (92.15 mol g-1h−1), respectively. Moreover, the apparent quantum efficiency (AQE) of IOBi2WO6/15Bi2O3 is 8.9 % at 420 nm. The enhanced photocatalytic activity is attributed to the synergy between the formation of the Bi2WO6/Bi2O3 S-scheme heterojunction and the construction of the IO structure. Based on the S-scheme mechanism, the mechanism and driving force of charge carriers’ transfer and separation in this study were investigated and discussed in detail by a density functional theory (DFT) calculation. This study demonstrates a very promising protocol to prepare the three-dimensional efficient charge carriers’ separation and fast migration heterojunction photocatalyst for practical applications.