Boron and nitrogen co-doped carbon nanosheets encapsulating nano iron as an efficient catalyst for electrochemical CO2 reduction utilizing a proton exchange membrane CO2 conversion cell

Electrochemical carbon dioxide (CO2) reduction, ideally in an aqueous medium, accounts for the sustainable storage of energy from renewable sources in the form of chemical energy in fuels or value-added chemicals. Herein, we report boron and nitrogen co-doped carbon nanosheets encapsulating iron nanocrystals (Fe/BCNNS) as a low cost, highly efficient and precious-metal-free electrocatalyst for the electrochemical reduction of carbon dioxide to formic acid. The porous architecture of the boron and nitrogen co-doped carbon nanosheets along with the active Fe-N-x, N and B sites synergistically allow better three phase contact to enhance the electrocatalytic activity of the cell. Both half-cell as well as full cell measurements have been performed with this particular catalyst. The proton exchange membrane (PEM) CO2 conversion cell is tested under a continuous flow of CO2 gas and is demonstrated to selectively produce a high yield of formic acid due to improved interaction between the catalyst and gas molecules. The maximum yield of formic acid achieved is as high as 94% after 60 min of reaction with Fe/BCNNS as both anode and cathode catalysts. It can be anticipated that such a facile synthesis strategy and excellent electrocatalytic performance of low-cost Fe/BCNNS catalyst can be easily scaled up for industrial applications in electrochemical CO2 conversion. (C) 2019 Elsevier Inc. All rights reserved.