Electrochemical ammonia synthesis via nitrate reduction over lithium incorporated CeO2

Ammonia (NH3) is a crucial chemical in the industrial sector, primarily employed for the production of fertilizers containing nitrogen, as well as nitric acid, polymers, and pharmaceuticals. Furthermore, it is being evaluated as a high-energy, carbon-neutral energy transporter. Currently, the production of NH3 is achieved by the energy-intensive Haber-Bosch process. This process utilizes fossil fuels as a hydrogen and energy source resulting in substantial carbon dioxide emissions. NH3 production from air, water, and renewable electricity using electrochemical processes has been suggested as a potential resolution for these problems. In this thesis, we employed CeO2 due to its multiple valence states, crystal structure, and electrochemical functionalities in electrochemical ammonia synthesis via nitrate (NO3-) reduction. Additionally, lithium metal dopants played a significant role in the reduction of nitrate to ammonia. Hollow sphere powder materials synthesized in nano size using the ultra spray pyrolysis method were characterized by XRD, XPS, Raman spectroscopy, SEM, and TEM. Electrochemical activity studies including chronoamperometry experiments were conducted and subsequently, the indophenol blue method was employed for the determination of ammonia. 10% Li-doped CeO2 yielded a faradaic efficiency (F.E) of 82.9%. Through studies involving Fe impregnation, the performance and efficiency were further enhanced, achieving an F.E of 94% and an NH3 yield rate of 1 mg h-1.mg-1. These results demonstrate the successful outcomes of nitrate reduction with lithium-doped CeO2 and the synthesis of an innovative and high-performance material for ammonia production.