Photocatalytic H2 production from ethanol aqueous solution using TiO2 with tungsten carbide nanoparticles as co-catalyst

Abstract

The effect of tungsten carbide as co-catalyst in the photocatalytic H2 production from ethanol aqueous solutions (25% v/v) is reported. The photocatalytic H2 production using WC/TiO2 systems, in which tungsten carbide NPs are dispersed onto TiO2, is compared with that of TiO2800 with morphological and structural characteristics similar to WC/TiO2 and with the hydrogen produced using commercial TiO2 P25 as reference. To this end, WxCy/TiO2, WC1-x/TiO2_US and WO3/TiO2 photocatalysts were prepared, characterized and tested. The preparation of WxCy/TiO2 was accomplished by using a sol-gel based method which was useful for preparing bulk tungsten carbides. The preparation of WC1-x/TiO2_US is reported by the first time using a sonication method from WC1-x and TiO2800. Materials were characterized using N2 physisorption, XRD, SEM-EDX, TEM-HRTEM, UV–vis RDS, XP and Raman spectroscopy. The presence of 2–3 nm NPs with different tungsten carbide crystalline phases (hexagonal WC and W2C and cubic WC1-x) was determined for WxCv/TiO2 photocatalyst, the solely presence of 2–5 nm cubic WC1-x NPs onto TiO2 was confirmed for WC1-x/TiO2_US.The presence of tungsten carbide NPs onto TiO2 improves the photocatalytic behavior of TiO2 in terms of hydrogen production. The effect of tungsten carbide NPs in the C2–C4 products derived from ethanol is discussed and the reusability of the photocatalyst is also studied.