Synthesis and application of carbon based materials for the construction of an artificial nitrogen cycle with electrochemistry This dissertation aims to contribute towards an artificial nitrogen cycle based on carbon based materials design by electrochemical nitrogen reduction with an electrochemical activated C2N material and nitrate reduction with a single bismuth site material. These two parts include materials design and mechanism interpreting with experiments combined with density functional theory (DFT) calculations. By building well defined catalytically active sites on heterogeneous carbon based materials in different dimensions it hopefully lights up a mild flame for the path to our ambitious goal artificial nitrogen cycle.