Modified TiO2-supported Pd-, Pt-, Ag- and Au-based photocatalysts with same metal content (0.5 wt%) prepared by deposition-precipitation with urea were investigated for hydrogen production via water splitting using methanol as hole scavenger at room temperature, atmospheric pressure and two purple lamps of 13 W simultaneously emitting 52.0 and 48.0% of UV-vis light. The obtained photomaterials were characterized using X-ray diffraction, conventional and high-resolution transmission electron and field-emission scanning electron microscopies and ultraviolet-visible diffuse reflectance spectroscopy. The surface modification of the support by hydrolysis and sol-gel processes, the nanoparticles nature and the stirring speed were studied. Two suitable methods for comparison of hydrogen production results between different research groups are also reported. The results have been demonstrated that Au- and Pt-based photocatalysts presented higher amount and production rate of hydrogen that the respective Ag and Pd-based ones for both 600 and 800 rpm, and also when are compared with previous reported.