Photocatalytic reduction of nitrate in the presence of hole scavenger has been studied by using TiO2-supported bimetallic catalysts for the first time. Compared with monometallic catalysts, bimetallic catalysts, especially Ni-Cu/TiO2 catalyst, show more excellent photocatalytic reduction activity. Furthermore, the effects of metal weight ratio, total metal content, different hole scavengers and pH value of the solution are also investigated. It is found that pH value of reaction solution plays an important role in the photocatalytic reduction of nitrate ions. A mechanism is proposed to discuss enhancement effect of the bimetallic catalyst in photocatalytic reduction of nitrate ions in this paper. (C) 2004 Elsevier B.V. All rights reserved.