Comparison of Typical Photocatalytic Systems with Intrinsic Plasmonic Photocatalysts Based on Strontium Niobate for Water Splitting

Abstract

We report in this Review the study of conventional semiconductor-based photocatalysts and the photocatalytic properties of SrNbO3. The history of photocatalysis, its basic principles, and the problems associated with its commercial application will be discussed. These problems can be partially alleviated by using plasmonic metal nanoparticle/semiconductor systems. Then, we will introduce a new intrinsic plasmonic photocatalyst, SrNbO3. Epitaxial films of SrNbO3 are grown as a metallic oxide by means of pulsed laser deposition. This unusual material has a band gap of 4.1 eV with a degenerate conduction band with a charge-carrier density exceeding 1022 cm?3. This large charge-carrier density gives rise to a plasmon that in turn causes a strong absorption in the red range of light; this was mistaken earlier by the community to arise from a mid-gap state. When oxygen is introduced into this system, a special planar defect is formed that progressively reduces the percolation of the metallic region. Within the metallic region an unusual coherent plasmonic effect is seen, which arises from strong electronic correlation. Such a strong optical absorption enables the material to generate hydrogen from water under solar irradiation. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim