Hydrogen production by Photocatalytic Degradation of Organic Substances Using Iron-Containing Metal-Ceramic Composites Under UV and Visible-Light Irradiation

Abstract

Metal-ceramic composites with ceramic matrix modified with semiconductors (SiN-SiC and TiN) were synthetized by Self-propagating high-temperature synthesis (SHS) technology. X-ray diffraction (XRD) analysis was used to determine the phase composition of the composites based on the nitrides of silicon, titanium, vanadium, and boron. Surface morphology of the composites was investigated by scanning electron microscopy (SEM), and the surface iron content was estimated using an energy-dispersive X-ray spectrometer for SEM (EDX-SEM). Optical properties of the composites were studied, and the band gap values of ceramic matrix semiconducting components were calculated. The comparative evaluation of photocatalytic efficiency of the composites has been done for hydrogen production from solutions of organic substances (HCOOH, H2C2O4, malic acid, citric acid, sucrose, and N2H4) under UV and visible light irradiation. It has been shown, that the high efficiency of photocatalytic hydrogen production under visible light irradiation depends on the composition of ceramic matrix containing semiconducting constituents, the nature of organic substances used, and the addition of H2O2 to the solution causing a photo-Fenton reaction. Also, the effect of eosin on photosensitization of the process was studied. The system of VN/N2H4 has been established to exhibit the highest efficiency of hydrogen production (300–560 μmol h−1 g−1).