Synthesis of SrTiO3-TiO2-CaTiO3/Cu2O composite for stable and efficient H2 generation in deionized water and river water

Abstract

Herein, the SrTiO3-TiO2-CaTiO3/Cu2O quaternary composite has been designed and prepared via one-step hydrothermal process followed by a NaBH4 reduction treatment. By comparing the H2 production rate (HPR) of Sr-Ti-Ca/Cu samples prepared by different Cu sources, it is found that Sr-Ti-Ca/Cu has the best H2 production performance when CuCl2 is as Cu source. As expected, the highest HPR of Sr-Ti-Ca/Cu sample is up to 5.088 mmol g−1 h−1, which is 195.7 times as higher as that of the Sr-Ti-Ca sample (0.026 mmol g−1 h−1) under the same conditions. Moreover, the HPR reached 0.692, 0.530 and 0.647 mmol g−1 h−1 in tap water, lake water and river water, indicating that the photocatalyst has high practicability in natural water sources. In addition, the experiment of the tap water composition effect on H2 production performance shows that NO3− and SO42− ions have great negative influence on the HPR. Compared with Sr-Ti-Ca, the light absorption of Sr-Ti-Ca/Cu extends over the entire visible region, the interface resistance decreases, and the photocurrent density increases. These results suggest that the well-designed dual p-n heterojunctions and dual type-II heterojunctions in Sr-Ti-Ca/Cu sample can enhance the light absorption in the ultraviolet region and realize the rapid separation and migration of photogenerated charge, thereby accelerating the production of H2. This work shows the strong advantage and potential of non-precious metal efficient photocatalyst system for producing H2 from deionized water and natural fresh water.