Photonic Crystals Assembled by SiO 2 @Ni/TiO 2 for Photocatalytic Reduction of CO 2
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Photonic Crystals Assembled by SiO2@Ni/TiO2 for Photocatalytic Reduction of CO2 Suli Wu1 · Weixia Yang1 · Zhipeng Meng1 · Lu Li2 · Shufen Zhang1 Received: 14 February 2020 / Accepted: 18 May 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Photonic crystal (PC) can manipulate light propagation due to the presence of photonic band gap (PBG). PBG can redistribute density of optical state. When the PBG overlaps with the emission of an emitter embedded in PC, the excited electrons will be prohibited from transferring to the ground state. Introducing PC with suitable PBG into photocatalyst will partially reduce the electron–hole combination and improve photocatalytic efficiency. Meanwhile, appropriate specific surface area of 3-D quasi-ordered structure can increase the contact area of catalysts and CO2 to provide more catalytic sites, which plays an important role in the improvement of photocatalytic activity. Herein, S iO2@Ni/TiO2 PCs with designed PBG were fabricated and applied as catalysts for photocatalytic C O2 reduction using [Ru(bpy)3]Cl2·6H2O as photosensitizer. The designed SiO2@Ni/TiO2 PCs has a suitable specific surface area and certain surface roughness, which can effectively adsorb C O2 for photocatalytic reduction. Meanwhile, the PBG of S iO2@Ni/TiO2 PCs matches well with the electron–hole combination energy of the photosensitizer, the electron–hole combination process from the excited state falling back to the ground state can be prevented partially. Suppressing the falling of excited electrons will make electrons transfer to the catalyst, thereby improving the photocatalytic performance. Graphic Abstract
Keywords SiO2@Ni/TiO2 photonic crystals · Photocatalytic reduction of CO2 · Specific surface area · Photonic band gap · Electron–hole combination energy Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10562-020-03263-3) contains supplementary material, which is available to authorized users. Extended author information available on the last page of the article
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1 Introduction Photonic crystal (PC) is a kind of material formed by the periodic arrangement of two or more materials with different refractive indices in space, which possesses a photonic band gap (PBG) [1, 2]. Light at a specific frequency matching the PBG will be selectively reflected, when the PBG locates in the visible light [3, 4]. Due to the excellent light manipulating ability of PC, many efforts were made to improve the photocatalytic effect by using PC [5–7]. Furthermore, PBG can redistribute density of optical state [8–10]. When the PBG overlaps with the emission of an emitter embedded in PC, the excited electrons will be prohibited from transferring to the ground state and the emission was reduced [11]. Therefore, we suppose that introducing PC with suitable PBG into photocatalyst can reduce the electron–hole combination and enhance the photocatalytic efficiency, which means that excited-state electrons will
