Chitosan-modified TiO2 as photocatalyst for ethanol reforming under visible light

This work reports the reforming of bio-ethanol on chitosan-TiO2 hybrid photocatalysts at ambient temperature. The influence of chitosan composition on the photocatalytic performance of chitosan-TiO2 hybrid was studied. The hybrids were characterized by CHN elemental analysis, nitrogen adsorption-desorption isotherms, thermogravimetric analysis, diffuse reflectance spectroscopy, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The results showed that the preparation variables used for the incorporation of chitosan on TiO2 promoted changes in the morphology, superficial area, crystal size and porosity of the photocatalyst, affecting the band gap of this semiconductor and consequently the reactivity of the chitosan-TiO2 hybrids. The catalysts were evaluated for hydrogen production from ethanol under visible light. It was demonstrated that the calcination temperature of 623 K and a chitosan content of 20% were the most appropriate preparation conditions and the resulting product displays a pore size of 1.9 nm, crystal size of 11.3 nm, BET area of 178 m(2) g(-1) and band gap of 2.92 eV. The calcination temperature of 623 K and incorporation of 20% of chitosan obtained the same results in the conversion rate of hydrogen in comparison to the pure TiO2 P25.