Boron-Doped Cu3Ni/BaTi4O9 Porous Composite by Regulating the Electronic Structure as High-Performance Photocatalysts for the H2 Evolution Reaction

In recent years, photocatalytic H2 evolution technology has been one of the hot topics to solve the energy crisis. The Cu3Ni/BaTi4O9 composite through hydrothermal and calcination treatment could provide photoelectrons under light irradiation, intriguing the hydrogen (H2) from water molecules. While pursuing a narrow band gap of such materials cannot rely on a simple composite, a chemical bonding contribution is expected to improve the photoexcited electrons by doping the heteroatoms. In this work, boron (B) doping was used to regulate the electronic structure of BaTi4O9 (BTO) and reduce its band gap. Simultaneously, the influence of calcination temperature on the structure and performance of catalysts was explored according to physical characterizations. Due to this, the B(3)-Cu3Ni/BTO photocatalyst possessed macropores with 1–2 μm diameter and abundant mesopores. Under visible light irradiation, the photocatalytic H2 evolution rate reached 318.06 μmol g–1 h–1 at a B doping level of 3%, as determined by gas chromatography analysis. It is 1.73 times that of the undoped B composite catalyst (184.14 μmol g–1 h–1) under the same conditions. Combining density functional theory calculations and experimental studies, it is confirmed that the B-doped form mainly exists in the form of Ti–O–B in BaTi4O9, reducing its band gap value and improving photocatalytic hydrogen evolution activity.