Production of hydrogen by water photo-splitting over commercial and synthesised Au/TiO2 catalysts

• Published in: Applied catalysis. B, Environmental Vol. 147; pp. 439 - 452
• Main Authors: Mendez, JAOrtega, Lopez, Cristina R, Melian, EPulido, Diaz, OGonzalez, Rodriguez, JMDona, Hevia, DFernandez, Macias, M
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.04.2014
• Subjects: Au plasmon; Catalysis; Gold; H2 production; Heat treatment; Methanol; Methyl alcohol; Photo-splitting; Photocatalysis; Photocatalysts; Sol gel process; Titanium dioxide; H2 production; Photo-splitting; Photocatalysis; Au plasmon; Methanol
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2013.09.029

•The SG750 photocatalyst at 2.0wt.% Au gave the highest H2 production yield per unit of surface area.•The highest production of H2 was obtained with the commercial photocatalyst KR.•The presence of Au results in a shift of absorption energy towards the visible light region.•The main degradation intermediates are formic acid, formaldehyde and CO2. H2 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 6.0wt.%, 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 3.5h using 1gL−1 of photocatalyst with methanol (25vol.%) as sacrificial agent. In addition to H2 generation, production of the main intermediates, formaldehyde and formic acid, and of CO2 was also evaluated. The commercial photocatalyst KR at 0.8wt.% Au had the highest H2 production of all the photocatalysts studied with 1542.9μmolh−1. Of the photocatalysts synthesised by our group, SG750 at Au loading of 2.0wt.% gave the highest H2 production of 723.1μmolh−1. The SG750 photocatalyst at Au loading of 2.0wt.% also had the highest H2 production yield per unit of surface area at 45.5μmolgh−1m−2.