A Spectroscopic Investigation of Photochemical Nitrogen Fixation

Photochemical nitrogen transformations were initially pioneered by a prominent Indian soil scientist, N.R. Dhar, in the 1930-40s[1]. Others continued to evaluate this process in the presence of liquid water, water vapor, and oxygen. These results remained unverified until 1977, when Schrauzer and Guth also began to investigate this process on natural minerals[2]. Since the 1970s photochemical nitrogen fixation has been widely studied on a number of photocatalyst[3]. Most conclude that nitrogen is reduce to ammonia through a direct electron-transfer based process. However, the reaction mechanism has not been clearly mapped using spectroscopic techniques. Here, we examine the reaction pathway for nitrogen fixation to ammonia on titania based photocatalyst using multiple spectroscopic techniques. We also aim to focus our talk on explaining the role hole scavengers play in enabling this reaction. [1]Dhar, N. R., and N. N. Pant. "Nitrogen loss from soils and oxide surfaces." Nature 153.3873 (1944): 115-116. [2] GN Schrauzer and TD Guth. Photocatalytic reactions. 1. Photolysis of water and photoreduction of nitrogen on titanium dioxide. Journal of the American Chemical Society, 99(22):7189–7193,1977. [3]Medford, Andrew J., and Marta C. Hatzell. "Photon-driven nitrogen fixation: current progress, thermodynamic considerations, and future outlook." Acs Catalysis 7.4 (2017): 2624-2643.