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

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 H-2 evolution rate on the Pt/MgO(in)-Ta3N5 photocatalyst reaches 22.4 mu mnol h(-1), which is ca. 17 times that of pristine Pt/Ta3N5 photocatalyst. (C) 2016 Elsevier Inc. All rights reserved.