New Intermediate band sulphide nanoparticles acting in the full visible light range spectra as an active photocatalyst

摘要: Nowadays one of the challenges materials science is to find new technologies that will be able make most renewable energies. An example proposals in this field are intermediate-band (IB) materials, which promise higher efficiencies photovoltaic applications (through intermediate band solar cells), or heterogeneous photocatalysis (using nanoparticles them, for light-induced degradation pollutants efficient photoevolution hydrogen from water). IB material consists a semiconductor gap level introduced [1], (IB), should partially filled by electrons and completely separated valence (VB) conduction (CB). This scheme (figure 1) allows an electron VB promoted IB, latter CB, upon absorption photons with energy below Eg, so can absorbed wider range spectrum current obtained without sacrificing photovoltage (or chemical driving force) corresponding full bandgap thus increasing overall efficiency. concept, applied photocatalysis, would allow using visible while keeping same redox capacity. It important note concept differs classic photocatalyst doping principle, essentially tries just decrease bandgap. type keep potential but use also lower photons. In our group several have been proposed, mainly application, based on extensively known semiconductors transition metals [2], examining DFT calculations their electronic structures. Here we refer In2S3 SnS2, contain octahedral cations; when doped Ti V formed according quantum (see e.g. figure 2). We used solvotermal synthesis method prepare nanocrystalline form thiospinel layered compound SnS2 (which undoped bandgaps 2.0 2.2 eV respectively) where cation substituted vanadium at ?10% level. substitution has studied, characterizing different physical techniques (TXRF, XRD, HR-TEM/EDS) 3) verifying UV spectrometry introduces sub-bandgap features predicted 4). For both sulphide (doped undoped) photocatalytic activity was studied following room temperature oxidation formic acid aqueous suspension, simple reaction easily monitored UV-Vis spectroscopy. The spectral response process measured collection pass filters only some wavelengths into system. Thanks active photodecomposition coincides samples) checked, proving samples increased, making possible cover all light range. Furthermore it checked these more photocorrosion resistant than toxic CdS witch well know frequently tests photocatalysis. These promising not cells) water; work direction now being pursued.