CO2 electroreduction on Mn-N-C and Ni-N-C electrocatalyst embedded in gas diffusion electrodes

Abstract

In today´s world, every human being faces problems like global warming, pollution and energy demand crises. The scientific community believes that the long term solution for these problems is reducing CO2 into energy-dense products. CO2 reduction reaction (CO2RR) requires active catalysts for efficient conversion. Developing catalysts based on earth-abundant elements for CO2RR is needed. Activity, selectivity and stability are the evaluation parameter for CO2RR catalysts. In this thesis, various manganese and nickel based nitrogen-doped carbon materials were synthesized and investigated as potential candidates for CO2RR aiming to achieve a minimum 50% faradic efficiency (FE) for carbon monoxide (CO) at -220 mA current, i.e. -194 mA/cm2 of current density. Optimised Ni-based catalysts show 58% FE for CO at -194 mA/cm2 with 112 mA/cm2 partial current density of CO, whereas Mn materials only favour hydrogen evolution reaction (HER), reaching a maximum 10 % FE for CO at -23 mA/cm2. A later part of this study includes various approaches to improve CO2RR activity, selectivity and stability, such as the addition of benzoxazine polymer, and changing precursors mass loadings.