Built-in electric field and oxygen absorption synergistically optimized an organic/inorganic heterojunction for high-efficiency photocatalytic hydrogen peroxide production

The production of hydrogen peroxide (H2O2) from oxygen and water is an attractive route for converting solar energy into chemical energy. In order to achieve high solar-to-H2O2 conversion efficiency, floral inorganic/organic (CdS/TpBpy) composite with strong oxygen absorption and S-scheme heterojunction was synthesized by simple solvothermal-hydrothermal methods. The unique flower-like structure increased the active sites and oxygen absorption. The existence of S-scheme heterojuntion facilitated the charge transfer across the built-in electric field. Without sacrificial reagents or stabilizers, the optimal CdS/TpBpy had a higher H2O2 production (3600 µmol g-1 h-1), which was 2.4 and 25.6 times than those of TpBpy and CdS, respectively. Meanwhile, CdS/TpBpy inhibited the H2O2 decomposition, thus increasing the overall output. Furthermore, a series of experiments and calculations were carried out to verify the photocatalytic mechanism. This work demonstrates a modification method to improve the photocatalytic activity of hybrid composites, and shows potential applications in energy conversion.