Comparative Study of Zn2Ti3O8 and ZnTiO3 Photocatalytic Properties for Hydrogen Production

Abstract

In the present work, zinc titanates (ZTO) as photocatalysts were synthesized, characterized, and evaluated aiming to study their photocatalytic properties for hydrogen production under visible-light irradiation and employing MeOH (methanol) and TEOA (Triethanolamine) as sacrificial agents. ZTO were synthesized by modified Pechini method. Characterization of materials consisted in TGA, XRD, TEM, EELS, BET, and UV–Vis. Surface interaction studies consisted of FT-IR spectroscopy and determination of MeOH and TEOA adsorption–desorption capacities on the ZTO by TGA. Zinc titanates were evaluated as photocatalyst for H2 production using an artificial visible light and monitored by GC. TGA results led to establish calcination temperatures of 550 °C (Zn2Ti3O8) and 700 °C (ZnTiO3) to reach their crystalline phases. XRD analysis of sample cds-ZTO found cubic Zn2Ti3O8 and traces of the ZnO crystalline phase, while p-ZTO exhibited a mixture of cubic and hexagonal ZnTiO3 crystalline phases. Surface area for cds-ZTO was 88 m2/g, while ZnTiO3 had 13 m2/g. Photocatalytic H2 production for cds-ZTO and p-ZTO using TEOA as sacrificial agent showed the highest photocatalytic activities generating 548 and 441 µmolH2/h.gcat. TEOA adsorption–desorption capacity was found superior on cds-ZTO and p-ZTO than that for MeOH on both samples.