Electrochemical Reduction of CO₂ to CO by N,S Dual‐Doped Carbon Nanoweb Catalysts

Abstract

Converting CO2 into useful chemicals through an electrocatalytic process is an attractive solution to reduce CO2 in the atmosphere. However, the process suffers from high overpotential, low activity, or poor product selectivity. In this study, N,S dual‐doped carbon nanoweb (NSCNW) materials were proposed as an efficient nonmetallic electrocatalyst for CO2 reduction. The NSCNW catalysts preferentially and rapidly converted CO2 into CO with a high Faradaic efficiency of 93.4 % and a partial current density of −5.93 mA cm−2 at a low overpotential of 490 mV. A small Tafel slope value (93 mV dec−1) was obtained, demonstrating a high rate for CO2 reduction. Moreover, the catalysts also exhibited a quite stable current‐density profile during 20 h with a high CO Faradaic efficiency above 90 % throughout the electrolysis reaction. The high catalytic performance of the catalysts for CO2 reduction could be attributed to synergistic effects associated with the structural advantages of 3 D carbon nanoweb structures and effective S doping of the carbon materials with the highest ratio of thiophene‐like S to oxidized S species.

Nitrogen and Boron Co‐Doped Carbon Spheres for Carbon Dioxide Electroreduction

“…The introduction of heteroatoms breaks some initial C−C bonds and forms new carbon‐heteroatom bonds in the carbon matrix, resulting in the creation of defects and unique heteroatom sites, which have been considered as catalytically active sites for CO 2 RR. When doping the pristine carbon with two kinds of heteroatoms, synergistic effects on the reaction pathways are expected to tune the activity and selectivity of CO 2 RR [24–30] . For instance, nitrogen and sulfur co‐doped carbon hierarchically porous carbon nanofiber membranes can achieve a CO Faradaic efficiency of 94%, higher than the nitrogen‐doped reference sample.…”

Recent Progress in Electrocatalytic Methanation of CO2 at Ambient Conditions

“…Based on the N and S dual‐doping, the carbon nanoweb serves as an efficient nonmetallic electrocatalyst for conversion of CO 2 into CO with a FE of 93.4%. [ 148 ] On the contrary, Li et al. found that S, N‐doped carbon exhibit a catalytic performance toward electrochemical reduction of CO 2 into CH 4 with a FE of 0.18%.…”

“…[147] Moreover, the catalytic activity of CO 2 RR by N-doped carbon materials highly relies on the amount and local electronic properties of N atoms in the carbon matrix, which determines the number of active sites and intrinsic catalytic nature, respectively. [148] Furthermore, among these N species in the carbon matrix, pyridinic N is the most active sites for CO 2 reduction followed by pyrrolic and graphitic N. [149] It is worth noting that Kumar et al proposed that it is the reduced/ positively charged carbon atoms rather than the electronegative nitrogen atoms responsible for the CO 2 reduction. [145] The positively charged quaternary N in the matrix are the sites for the stabilization of *CO 2…”

Plasma-regulated N-doped carbon nanotube arrays for efficient electrosynthesis of syngas with a wide CO/H2 ratio

“…Though the intrinsic activity of carbon materials is poor, the introduction of heteroatoms (N, S, B, etc.) can effectively promote their electrochemical activity and selectivity [19][20][21][22][23]. Taking N-doped carbon materials as the examples, the doping N atoms exist in the forms of pyridinic N, pyrrolic N, graphitic N, and oxidized N in the carbon materials.…”