Photocatalytic reduction of nitrate (NO 3−) is a green and potentially inexpensive technique for reducing NO 3− pollution in ground water. TiO 2-based photocatalysts have been studied extensively for this purpose. In the present study, the semiconducting catalyst CuFe 0.7 Cr 0.3 S 2 was applied to NO 3− reduction. Loading this catalyst with metal co-catalysts (Ru, Au, Cu, Ag, Pt, and Pd) greatly increased the rate of NO 3− reduction and the N 2 selectivity. In addition, there was a synergistic enhancement of the photocatalytic performance when the catalyst was loaded two co-catalysts. For example, the catalyst loaded with Pd and Au at mass fractions of 0.75% and 3%, respectively, could photocatalyze the complete reduction of NO 3− in a 100 ppm N aqueous solution with 100% N 2 selectivity in less than 5 h with UV irradiation. However, with an inner irradiation from a full-arc Xe lamp, the NO 3− conversion rate reduced to 0.065 mg N/h, probably because of the low density of the photoexcited electrons. The results show the potential of metal sulfides for photocatalytic reduction of NO 3−, and the possibility of use of visible light.