Production of hydrogen by water photo-splitting over commercial and synthesised Au/TiO sub(2) catalysts

• Published in: Applied catalysis. B, Environmental Vol. 147; pp. 439 - 452
• Main Authors: Mendez, J A Ortega, Lopez, Cristina R, Melian, E Pulido, Diaz, O Gonzalez, Rodriguez, J M Dona, Hevia, D Fernandez, Macias, M
• Format: Journal Article
• Language: English
• Published: 05-04-2014
• Subjects: Catalysis; Gold; Heat treatment; Methyl alcohol; Photocatalysis; Photocatalysts; Sol gel process; Titanium dioxide
• ISSN: 0926-3373
• DOI: 10.1016/j.apcatb.2013.09.029

H sub(2) production from methanol/water photo-splitting was compared using various commercial photocatalysts (Evonik P25 (P25), Hombikat UV-100 (HB) and Kronos vlp7000 (KR)) and others synthesised with a sol-gel-hydrothermal (HT) process and a sol-gel method followed by calcination (SG400 and SG750). All photocatalysts had been surface modified with Au at different concentrations, from 0.2 to 6.0 wt.%, using the photodeposition method. A complete characterisation study of the different photocatalysts was performed (BET, XRD, TEM, SEM-EDX, FTIR, UV-vis Reflectance Diffuse Spectra and aggregate size). The experiments were conducted for 3.5 h using 1 g L super(-1) of photocatalyst with methanol (25 vol.%) as sacrificial agent. In addition to H sub(2) generation, production of the main intermediates, formaldehyde and formic acid, and of CO sub(2) was also evaluated. The commercial photocatalyst KR at 0.8 wt.% Au had the highest H sub(2) production of all the photocatalysts studied with 1542.9 [mu]mol h super(-1).Of the photocatalysts synthesised by our group, SG750 at Au loading of 2.0 wt.% gave the highest H sub(2) production of 723.1 [mu]mol h super(-1). The SG750 photocatalyst at Au loading of 2.0 wt.% also had the highest H sub(2) production yield per unit of surface area at 45.5 [mu]mol g h super(-1) m super(-2).