Owing to simplicity, eco-friendly, and carbon dioxide free in reaction, Hydrogen production by water splitting is attracting enormous attention for solar energy conversion. Water splitting technology, which is regarded as the third-generation-solar energy utilizing technology, has been expected as the key of renewable energy generation since only solar energy and water are needed as the resources.Light absorption, charge (electron-hole) separation, and charge transfer at interfaces are regarded as the most important factors for photoelectrodes in water splitting. Internal electrical field induced by ferroelectric polarization in perovskite oxides can be applied in photoelectrochemical water splitting effectively in this point of view. Perovskite oxides can provide better charge separation ability and prevent electron-hole recombination due to the spontaneous ferroelectric polarization and subsequent band bending at the interfaces. In this work, we report photoelectrochemical properties of ferroelectric perovskite oxides - potassium niobate-barium nickel niobate (KNbO3-BaNiNbO3, KBNNO). For converting solar energy to electric and electrochemical energy, KBNNO is a fascinating material with the internal ferroelectric polarization (20 �C/cm2) and suitable band gap energy (KBNNO: 1.3-2.0 eV). We show the reduction of charge recombination and improvement of the quantum efficiencies due to the ferroelectric polarizations in the materials, which are confirmed by experiments with polarization switching. Our results suggest the promising use of ferroelectric perovskite oxides for water splitting photoelectrodes.

Ferroelectric polarization of perovskite oxides for water splitting photoelectrodes

248th National Meeting (2014)

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