Gold nanoparticles deposited on TiO2 Degussa P25, prepared by deposition-precipitation with urea, were studied in the photocatalytic hydrogen production. The effect of parameters such as mass of catalyst, gold loading, thermal treatment, and atmosphere of treatment was evaluated and optimized. The presence of metallic gold on the titania surface showed to have contributed to the high improvement in the activity of bare TiO2 for hydrogen generation under UV light (lambda = 254 nm) using a lamp of low energy (2 W) consumption. The optimal gold loading for the photocatalysts was 0.5 wt.%, the mass of catalyst in the reactor was 0.5 g/L in a water/methanol 1:1 vol. solution, and the thermal treatment that produced the most active gold nanoparticles was found at 300 degrees C. The photocatalysts thermally treated under hydrogen at 300 degrees C produced 1492 mu mol g(-1) h(-1) of hydrogen; the same catalyst activated in air produced 1866 mu mol g(-1) of hydrogen. (C) 2013 Elsevier B.V. All rights reserved.