Formic acid (FA) photocatalytic degradation using nickel doped TiO2 (Ni-TiO2) coated on silica grain (Ni-TiO2/SiO2) by sol-gel method has been studied. Nickel with a different molar ratio as , , and % mole was used in this study. Samples were characterized by XRD, SEM, and UV-vis spectroscopy. | Vietnam Journal of Science and Technology 55 (4C) (2017) 174-179 PHOTOCATALYTIC DEGRADATION OF FORMIC ACID INAQUEOUS WITH Ni DOPED TiO2 COATED ON SILICAGEL Nguyen Thi Thanh Hai1, Nguyen Manh Nghia2, Nguyen Thi Hue1, Nobuaki Negishi3 1 Institute of Environmental Technology, VAST, 18 Hoang Quoc Viet, Ha Noi, Viet Nam 2 Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Ha Noi, Viet Nam 3 Environment Management Research Institute, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8560 Japan * Email: nguyenhai2t@ Received: 1 August; Accepted for publication: 17 October 2017 ABSTRACT Formic acid (FA) photocatalytic degradation using nickel doped TiO2 (Ni-TiO2) coated on silica grain (Ni-TiO2/SiO2) by sol-gel method has been studied. Nickel with a different molar ratio as , , and % mole was used in this study. Samples were characterized by XRD, SEM, and UV-vis spectroscopy. Conditions such as dark, ultraviolet-visible and visible light were performed to assess the photocatalytic ability of Ni-TiO2/SiO2. The results showed that, catalyst samples had uniform nanosize, anatase crystalline structure and the band-gap energy of Ni-TiO2/SiO2 was lower than that of TiO2/SiO2 sample. The highest photocatalyst activities were obtained at % mol of Ni for both irradiations. The FA concentration was not changed in the dark condition. Under ultraviolet-visible irradiation, FA concentration decreased from 10-4 mM to , and mM with , and % mole of Ni, respectively. With visible light condition, FA concentration decreased from 10-4 mM to mM when Ni dopant amount was % mole. Change in FA concentration was negligible with and % mole of Ni dopant amount. It proved that the photocatalytic activity of Ni-TiO2/SiO2 under visible light irradiation was generated by doping a small amount of nickel into TiO2. However, under visible light irradiation with
