Boosting Effect of Nitrogen and Phosphorous Co-doped Three-Dimensional Graphene Architecture: Highly Selective Electrocatalysts for Carbon Dioxide Electroreduction to Formate

Electrocatalytic CO2 reduction (ECR) is regarded as an alternative strategy for tackling the energy demand problem as well as environmental issues such as global warming. The development of highly selective and stable, environmentally friendly, energy-efficient, and cost-natural advanced electrocatalysts is critical to facilitating this kinetically slow process. Herein, it has been aimed to form hierarchically ordered electrochemically active sites on three-dimensional graphene architecture as well as get benefit from the synergistic effect of co-doping of nitrogen and phosphorous, and thereby boosting the CO2 conversion. Therefore, metal-free nitrogen and phosphorous co-doped three-dimensional graphene (N,P-3DGN) architecture has been fabricated via a facile, scalable one-step microwave-assisted hydrothermal production pathway. N,P-3DG possesses a higher electrochemical active area and electrical conductivity than N- or P-doped graphene structures, facilitating electron transfer from CO2 to its radical anion or other key intermediates. Therefore, as-fabricated N,P-3DG structure with hierarchically ordered three-dimensional ion highways offered high faradaic efficiency of 93.7% for formate production at - 1.3 V (vs. Ag/AgCl) at a reasonable overpotential of 0.5 V. The onset potential of N,P-3DG has been found to be - 0.96 V (vs. Ag/AgCl), which is more positive than that of the three-dimensional graphene structure (3DG) (- 1.53 V). The N,S-3DG electrocatalyst successfully hindered the hydrogen evolution reaction and demonstrated stable electrocatalytic activity towards ECR. The results showed that the unique structure and synergistic effect of co-doping N,P atoms with C atoms pointed in the direction of conversion CO2 to formate.

Automated summary

The study focuses on the development of metal-free nitrogen and phosphorous co-doped three-dimensional graphene architecture for electrocatalytic CO2 reduction, which exhibits high faradaic efficiency and electrical conductivity, indicating potential for enhancing CO2 conversion.