Photocatalytic reduction of −NO₃${{\text{NO}}_3}^{\mathrm{-}}$ over CuFe_0.7Cr_0.3S₂ (CFCS) was studied in detail.

Various cocatalysts were loaded to CFCS, including Ru, Au, Cu, Ag, Pt, and Pd.

High efficiency and N₂ selectivity were achieved when loading both Pd and Au.

−NO₃${{\text{NO}}_3}^{\mathrm{-}}$ in 100 mL solution (100 ppm N) was converted to N₂ in 4.5 h under UV light.

With irradiation from a Xe lamp, it gave a −NO₃${{\text{NO}}_3}^{\mathrm{-}}$ conversion rate of 0.065 mg N/h.