TiO2 photocatalyst was prepared by sol-gel method, and then loaded with 1.0 wt.% Pt by impregnation-chemical reduction method (denoted as PT). Photocatalytic reforming (PR) of C3-polyols (glycerol, propyleneglycol, and isopropanol) which have similar carbohydrate structure but possess different number of OH groups for H-2 production over PT was performed to study the role of their OH groups in the reforming reaction. The results indicated that the H-2 evolution rate and the mineralization efficiency of polyols (oxidized to CO2) are highly correlated with the number of OH groups they contain. The more OH group it has, the higher H-2 evolution rate can be obtained, as well as the generation of CO2. The roles of the OH group were discussed in terms of providing an anchor for the chemical adsorption of polyols to the PT and serving as an effective holes scavenger to trigger the reforming reaction. For a polyol molecule, only OH directly connected segment can be effectively converted to H-2 and CO2 via the PR process. (C) 2011 Elsevier BM. All rights reserved.