The propionic acid (HPr) is one of the main by-products during fermentative H2 process. To efficiently convert HPr to H2 gas, photocatalytic H2 production from HPr solution with the use of Pt/TiO2 photocatalyst under ultraviolet light has been studied in this research. The Pt/TiO2 photocatalyst has been prepared by the sol–gel method and further characterized by X-ray diffraction, TEM and XPS. Effects of Pt loading amount, HPr concentration, initial pH value on photocatalytic H2 production have been investigated in detail. From practical point of view, the H2 evolution from HPr solution under UV irradiation for prolonged time has been studied as well. The Langmuir model can be able to describe the relationship between HPr concentration with the maximum rate of H2 production. The apparent quantum efficiency and apparent energy conversion efficiency are found to 1.65 and 0.72%, respectively. To better understand the photocatalytic H2 process over Pt/TiO2, a possible mechanism for the degradation of HPr has been proposed as well. Based on our results, an efficient route for hydrogen production from renewable biomass can be established by coupling biological H2 production process with photocatalytic H2 production process. Copyright © 2010 John Wiley & Sons, Ltd.