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! The removal of NO3 by a CuCrO2-mediated catalytic photoprocess was investigated under mild conditions. The delafossite CuCrO2 exhibits an excellent chemical stability over the whole pH range and relatively a large specific surface area when elaborated by chemical means. The optical gap was found to be 1.28 eV, close to the optimal value ! required for terrestrial applications. The conduction band is located at !1.06 VSCE and thus lies below the NO3 level leading to a thermodynamically favorable nitrate reduction under visible light. The possibility !of identifying the s! 3 ! reaction products via the intensity-potential characteristics 1.was explored. The reaction of NO3 proceeds in ! competition with the water reduction and seems to be the major reason in the regression of the photoactivity during 3 prolonged testing. The complete conversion occurs in less than ~4 h with a quantum efficiency of ~2%. .