Photochemical Nitrogen Fixation on Titania

Abstract

Photocatalysis is the ideal solution to sustainable ammonia synthesis, as it will enable the distributed production of fertilizers and fuels from reactants that are readily available at ambient conditions: air, water and photons. Given the massive amount of energy currently expended to produce and transport fertilizer, such a process would have an enormous impact on energy consumption and carbon emissions [1,2,3]. Photocatalytic nitrogen reduction has been demonstrated over titania catalysts, although the production rates are too low to be practical. Despite the enormous promise of this reaction, there is little understanding of the fundamental chemical and physical processes that enable it. In this presentation, defects, like oxygen vacancies, and dopants like iron and carbon have been demonstrated to enhance photocatalytic activity for TiO2 for nitrogen fixation. The results indicate that the defects and dopants aid in promoting nitrogen adsorption which consequently may drive photocatalytic performance. Furthermore, insight acquired through ambient pressure XPS and DRIFTs provide new insight into the role this process may play in natural environments. [1] 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. [2]Schrauzer, G. N., Strampach, N., Hui, L. N., Palmer, M. R., & Salehi, J. (1983). Nitrogen photoreduction on desert sands under sterile conditions. Proceedings of the National Academy of Sciences, 80(12), 3873-3876. [3]Doane, T. A. (2017). The Abiotic Nitrogen Cycle. ACS Earth and Space Chemistry, 1(7), 411-421.