Hydrogen Production from Aqueous Methanol Solutions Using Ti–Zr Mixed Oxides as Photocatalysts under UV Irradiation

Pérez-Larios Pérez-Larios,Gómez Gómez,Rico Rico,Vargas Vargas,González-Silva González-Silva,Anaya-Esparza Anaya-Esparza

doi:10.3390/catal9110938

Abstract

The synthesis and characterisation of Ti–Zr mixed oxides containing 1 to 10 wt.% of Zr is herein reported. In addition, the samples were tested as photocatalysts in the generation of hydrogen from aqueous methanol solutions. The solids were prepared by sol-gel and then characterised by X-ray diffraction, high resolution electron microscopy, X-ray photoelectron spectroscopy, physisorption of nitrogen, scanning electron microscopy, UV-vis and Raman spectroscopies. The results show the presence of anatase as a predominant structure and the oxides present larger specific surface areas than that of pure titania. A maximum value of 168 m2/g was determined for the sample with 5 wt.% of zirconium. The calculated band gap energies varied from 3.05 to 3.15 eV. It was observed that the greater the zirconium content in the solid, the higher the generation rate of hydrogen when testing the Ti–Zr solids as photocatalysts. Under our experimental conditions, the best catalyst, Ti–Zr oxide with 10 wt. % Zr, showed a production rate of 2100 μmol of H2/h which was about tenfold higher than that observed for pure titania.

Highlights

Hydrogen is considered one of the most promising fuels for the future
The images are comprised of agglomerates and no apparent differences are noticed when zirconium was incorporated into titania
A clear increase in area is observed when zirconium is augmented until the TZr-5 sample and a slight decrease was noticed for TZr-10

Summary

Introduction

Hydrogen is considered one of the most promising fuels for the future. Most of the available hydrogen in the world is produced from the reforming of methane [1]. Carbon monoxide generated from this process eventually contaminates and contributes to the high level of CO2 in the atmosphere. The photocatalytic generation of hydrogen from water only produces O2 and. H2 and it is a very attractive and promising process. For a photocatalytic process to be economical and sustainable, the development of efficient catalysts and the use of a renewable energy source are required [2]. Since the pioneering work published by Fujishima and Honda on the photocatalytic generation of hydrogen from water [3], extensive research on this subject has been observed worldwide

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