The metal and nitrogen-doped carbon catalysts are one of the most promising solutions for the electrochemical carbon dioxide reduction reaction. However, the complex and energy-intense procedure to synthesize catalysts hinders the scalable application. Moreover, the state-of-the-art carbon supports, i.e., graphene and carbon nanotube, each have their own disadvantage. Graphene is rich in active sites but tends to aggregate, while the carbon nanotube suffers from a low density of active sites. In this work, we developed a 3D carbon nanotube and carbon nanosheet hybrids by a one-step chemical vapor deposition method. The single atomic nickel sites in the system significantly enhance carbon dioxide reduction. Nickel nanoparticles are encapsulated by graphitic carbon layers grown from the chemical vapor deposition process and the competing hydrogen evolution reaction is suppressed. The catalyst in this work delivers a stable CO Faradaic efficiency of 91% with a partial CO current density of 28.9 mA/cm2 at -0.74 V in the traditional H-Cell setup. The same catalyst achieves commercially viable current densities up to 600 mA/cm2 in a flow cell with CO selectivity above 85%. These results are among the top-level performances in the literature for carbon-based catalysts to the best of our knowledge. Furthermore, the catalysts developed in this work are synthesized at a moderate temperature without any oxidant treatment or acid washing in an energy-efficient and environmentally benign way.

Synthesis of hierarchical carbon catalysts by chemical vapor deposition for efficient CO2 electrolysis at commercially viable current densities

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.