Curvature Effect of Pyridinic N-Modified Carbon Atom Sites for Electrocatalyzing CO2 Conversion to CO

Carbon material is considered a promisingelectrocatalystfor theCO(2) reduction reaction (CO2RR); especially,N-doped carbon material shows high CO Faradic efficiency (FECO) when using pyridinic N species as the active site. However, inthe past decade, more efforts were focused on the preparation of variouscarbon nanostructures containing abundant pyridinic N species andfew researchers studied the electronic structure modulation of thepyridinic N site. The curvature of the carbon substrate is an easilycontrollable parameter for modulating the local electronic environmentof catalytic sites. In this research, carbon nanotubes (CNTs) withdifferent diameters are applied to modulate the electronic environmentof pyridinic N by the curvature effect. The pyridinic N sites dopedon CNTs with the average curvature of 0.04 show almost 100% FECO at the current density of 3 mA cm(-2) at-0.6 V vs RHE and 91% FECO retention after 12 h test, which is superior to most of the carbon-based electrocatalysts.As demonstrated by density functional theory simulation, the pyridinicN site forms a strong local electric field around the nearby C activesite and protrudes out of the curved CNT surface like a tip, whichremarkably enriches the protons around the adsorbed CO2 molecule.

Automated summary

Carbon materials, particularly N-doped carbon materials, have shown high CO Faradic efficiency (FECO) in the CO2 reduction reaction (CO2RR). However, previous studies focused more on preparing carbon nanostructures with abundant pyridinic N species, rather than studying the modulation of the pyridinic N site's electronic structure. In this research, carbon nanotubes with different diameters were used to modulate the electronic environment of pyridinic N through the curvature effect. The study found that pyridinic N sites doped on carbon nanotubes with an average curvature of 0.04 exhibited almost 100% FECO and 91% FECO retention after a 12-hour test, surpassing most carbon-based electrocatalysts. Density functional theory simulation revealed that the pyridinic N site forms a strong local electric field and protrudes out of the curved carbon nanotube surface, enriching the protons around the adsorbed CO2 molecule.