Ranking the relative CO2 electrochemical reduction activity in carbon materials

Abstract

To reverse the ever-increasing trend of the CO2 concentration in the atmosphere, human needs to develop a killer “catalyst”, which could convert the anthropogenic CO2 back into high value-added or energy-storage molecules, not under the natural photosynthesis Calvin cycle, but through an artificial CO2 reduction pathway. In the race to this emergent technology, the electrochemical reduction of CO2 (CO2RR) with carbon based catalyst becomes one of the frontrunners. However, the carbon-based catalysts are genetically complex, with edge, strain, intrinsic topological defect, and doping effects, coexisting and affecting the catalysis behavior. Without a relative activity ranking system under the same metrics, unveiling the mechanism and improving the catalyst would become formidable. Here we assessed different carbon materials’ CO2RR performance under standard experimental conditions. The catalytic activities were evaluated and sequenced by their cathodic potential, characterized with the peak CO faradic efficiency. The doping effect is leading in the sequence, followed with the other three factors, all of which are superior to the pristine sp2 carbon material.