Solvothermal 방법을 이용한 Hexagonal Nickel Titanate의 합성 및 광촉매 특성 연구

Abstract

Recently, solar energy have been recognized as a one of the most attractive renewable energy alternatives to fossil fuels because of their non-polluting, infinite and abundant aspect. However, due to the diffuse and intermittent nature of solar irradiation, an energy harvested from the sun must be efficiently converted into chemical fuels that are storable, transportable, and usable upon demand. The use of solar energy to convert various types of energy source have been requested to be a necessary technology for the future. Photocatalyst is a promising an energy converter to obtain other energy from solar energy. As a energy conversion process, a water splitting by the photocatalyst occurs through several steps such as photon absorption, charge separation, carrier diffusion, carrier transport and surface chemical reactions. A well-known photocatalyst like TiO2, and ZnO have been used to numerous fields as a disadvantage in the efficiency of solar energy absorption even they have a relatively wide band gap energy of 3.2 eV. However, it is requested that their absorption range should be widen to visible light for better energy conversion efficiency. To handle this approach, various researches have been approached to improve photon absorption, doping, solid solution, dye sensitization, localized surface plasmon resonance effect, etc. Materials design is one of approaches for suitable photocatalytic properties as well. Recently, Nickel Titanate has attracted an attention for applications including semiconducting photocatalyst, electrode of fuel cells and batteries, coatings, sensors etc, because of their a narrow band gap of ~2.18 eV and suitable photochemical stability. In this study, synthetic approach of hexagonal NiTiO3 photocatalyst are reported and their photocatalytic performances are demonstrated. Based on solution based approach, our synthetic reaction was controlled by reaction duration and reaction temperature etc. Interestingly, hexagonal NiTiO3 photocatalyst was changed to porous structure through annealing process. Morphology-dependent and size-dependent photocatalytic properties were compared with dye degradation.