Magnesia interface nanolayer modification of Pt/Ta3N5 for promoted photocatalytic hydrogen production under visible light irradiation

• A magnesia interface engineering strategy was applied to the Pt/Ta3N5 photocatalytic system.
• Enhanced H2 evolution rate was achieved by the magnesia interface nanolayer (MIN) modification.
• MIN bridges the passivated Ta3N5 semiconductor and the uniformed Pt cocatalyst.
• Compatible co-catalyst/semiconductor interface benefits the photocatalytic water splitting performance.

Deposition of a co-catalyst is a general strategy for promoting the water splitting performance of semiconductor-based photocatalysts, but the interface barrier of the co-catalyst/semiconductor system often leads to unfavorable interfacial charge transfer and separation. In this work, the interface issue of the Pt/Ta3N5 proton reduction system was addressed via a magnesia interface nanolayer (MIN) modification strategy, and its effect on the structure and properties of both the Ta3N5 semiconductor and the Pt co-catalyst was investigated. UV–visible diffuse reflectance spectroscopy, field emission scanning electron microscopy, and high-resolution transmission electron microscopy characterizations indicate that the MIN can not only effectively passivate the Ta3N5 semiconductor, but also favor the deposition of Pt co-catalyst with small particle size and uniform dispersion, which can increase the catalytic active sites and enlarge the interfacial contact area between Ta3N5 and Pt. Time-resolved infrared spectroscopy further evidences that the promoted charge separation process is achieved by this magnesia interface engineering strategy. Based on our modification, the optimal H2 evolution rate on the Pt/MgO(in)–Ta3N5 photocatalyst reaches 22.4 μmol h−1, which is ca. 17 times that of pristine Pt/Ta3N5 photocatalyst.

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