IEF-11 combined with g-C₃N₄ for the first time to construct S-mechanism heterojunction photocatalyst. The IEF-11/g-C₃N₄ heterojunction photocatalysts exhibit excellent photocatalytic hydrogen production performance in pure water without sacrificial agents. The rate of overall water splitting for H₂ production can reach 576 μmol/g/h, which is 8 times than that of g-C₃N₄ and 23 times of IEF-11.

Abstract

Construction of S-scheme heterojunction offers a promising way to enhance the photocatalytic performance of photocatalysts for converting solar energy into chemical energy. However, the photocatalytic H₂ production in pure water without sacrificial agents is still a challenge. Herein, the IEF-11 with the best photocatalytic H₂ production performance in MOFs and suitable band structure was selected and firstly constructed with g-C₃N₄ to obtain a S-scheme heterojunction for photocatalytic H₂ production from pure water. As a result, the novel IEF-11/g-C₃N₄ heterojunction photocatalysts exhibited significantly improved photocatalytic H₂ production performance in pure water without any sacrificial agent, with a rate of 576 μmol/g/h, which is about 8 times than that of g-C₃N₄ and 23 times of IEF-11. The novel IEF-11/g-C₃N₄ photocatalysts also had a photocatalytic H₂ production rate of up to 92 μmol/g/h under visible light and a good photocatalytic stability. The improved performance can be attributed to the efficient separation of photogenerated charge carriers, faster charge transfer efficiency and longer photogenerated carrier lifetimes, which comes from the forming of S-scheme heterojunction in the IEF-11/g-C₃N₄ photocatalyst. This work is a promising guideline for obtaining MOF-based or g-C₃N₄-based photocatalysts with great photocatalytic water splitting performance.