주제어 : 질산성 질소 저감 반응, Nanosized TiO2, SMSI, 물 Abstract : In this study, we synthesized TiO2 supports with nanosized crystalline structure by solvothermal method and prepared TiO2 supported Pd-Cu catalysts. It was shown that the crystalline size of TiO2 support in the catalyst influenced on the catalytic activity of nitrate reduction in water. The catalyst with the smaller crystalline size of TiO2 support presented faster nitrate reduction rate, but had low nitrogen selectivity due to high pH environment of reaction medium during the reaction. Through injection of carbon dioxide as a pH buffer, the nitrogen selectivity increased by about 60%. Furthermore, we investigated that the relationships between the catalytic performance and the physicochemical properties of the prepared catalysts characterized by N2 adsoprtion-desorption, X-ray diffraction (XRD), H2-temperature programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS).