Precise regulation of phosphorus in nitrogen-coordinated porous carbon spheres for tunable CO2 electroreduction to syngas

Abstract

The production of high-demand syngas with tunable ratios by CO2 electroreduction has attracted considerable research interest. However, it is challenging to balance the evolution performance of H2 and CO with wide H2/CO ratios, while maintaining high efficiency. Herein, nitrogen-coordinated hierarchical porous carbon spheres with varying phosphorus content (PxNC-T) are assembled to regulate syngas production performance. The precise introduction of P modulates the local charge distribution of nitrogen-coordinated carbons, thereby accelerating the protonation process of ∗CO2-to-∗COOH and promoting moderate H∗ adsorption. Specifically, syngas with wide H2/CO ratios (0.60-4.98) is obtained over a low potential range (-0.46 to -0.86V vs. RHE). As a representative, P1.0NC-900 presents a remarkable current density (-152 mA cm-2) at -1.0V vs. RHE in flow cells and delivers a decent peak power density (1.93 mW cm-2) in reversible Zn-CO2 batteries. Our work provides valuable insights into the rational design of carbon-based catalysts for CO2 reduction.