Metal‐Free Fluorine‐Doped Carbon Electrocatalyst for CO₂ Reduction Outcompeting Hydrogen Evolution

Abstract

The electrochemical CO reduction (ECDRR), as a key reaction in artificial photosynthesis to implement renewable energy conversion/storage, has been inhibited by the low efficiency and high costs of the electrocatalysts. Herein, we synthesize a fluorine-doped carbon (FC) catalyst by pyrolyzing commercial BP 2000 with a fluorine source, enabling a highly selective CO -to-CO conversion with a maximum Faradaic efficiency of 90 % at a low overpotential of 510 mV and a small Tafel slope of 81 mV dec , outcompeting current metal-free catalysts. Moreover, the higher partial current density of CO and lower partial current density of H on FC relative to pristine carbon suggest an enhanced inherent activity towards ECDRR as well as a suppressed hydrogen evolution by fluorine doping. Fluorine doping activates the neighbor carbon atoms and facilitates the stabilization of the key intermediate COOH* on the fluorine-doped carbon material, which are also blocked for competing hydrogen evolution, resulting in superior CO -to-CO conversion.

Composition Tailoring via N and S Co‐doping and Structure Tuning by Constructing Hierarchical Pores: Metal‐Free Catalysts for High‐Performance Electrochemical Reduction of CO2

“…[20,31] We hypothesize that the doped species within NSHCF is the origin of the disparity in the catalytic activity (for example,N -doped carbons have excellent CO 2 RR capabilities). [17] As calculation results shown in Figure 3b,t he lower Gibbs free energy barrier of 1.01 eV for *COOH occurs at pyridinic N adjacent to carbon-bonded Sa tom, consistent with 105 mV dec À1 Tafel slope and 94 %F aradaic efficiencyo f CO at À0.7 V RHE using NSHCF900. DFT calculations based on the structure model in the Supporting Information, Figure S17 and Table S2 were conducted to further explore the possible role of nitrogen-and sulfur-doping played in CO 2 RR.…”

“…[16,17] Recently,n anostructured carbon materials have emerged as alternative electrocatalysts to metal-and metal oxide-based counterparts for CO 2 RR. [16,17] Recently,n anostructured carbon materials have emerged as alternative electrocatalysts to metal-and metal oxide-based counterparts for CO 2 RR.…”

“…[18][19][20][21][22][23][24][25] In our study,N-doped hierarchically porous carbon nanofiber (NHCF900;S upporting Information, Figure S15) only yields 63 %F aradaic efficiencyfor CO in CO 2 RR, which is significantly lower than that of NSHCF900, signifying the importance of Ss pecies.T he relationship between the nitrogen and sulfur contents in catalysts and the associated CO 2 RR activity is illustrated in the Supporting Information, Figure S16, which demonstrates that pyridinic Ni st he dominant active sites for CO 2 RR, and the presence of carbon-bonded Sc an greatly enhance the catalytic activity. [17,21] This difference can be attributed to the higher spin density and charge delocalization caused by greater polarizability and larger atomic size of doped S atoms. It has been reported that the formation of adsorbed *COOH is the rate-determining step for the CO 2 -to-CO reduction, and the CO generation can be inhibited by high Gibbs free energy of *COOH.…”

Shock Exfoliation of Graphene Fluoride in Microwave

“…Its large specific surface area is beneficial to the diffusion kinetics of lithium ions and enables electrochemical storage and release of high‐density energy . F‐doped carbon can also be used as an efficient catalyst for electrochemical CO 2 reduction, in which the incorporation of F can activate adjacent C atoms and facilitate the catalytic reactions …”

Isolated Square‐Planar Copper Center in Boron Imidazolate Nanocages for Photocatalytic Reduction of CO2 to CO

“…Figure S19 indicated that the EPR signal for BIF-29 decrease in density with irradiation time under nitrogen atmosphere.A sacomparison, the EPR signal of Icoordinated BIF-33 keep nearly unchanged. [25] In addition, from the density of states of two models,itisfound that BIF-29 without I À delivers anew state in the conduction band near the Fermi level (Figure 3d), indicating enhanced reactivity in BIF-29 compared to the BIF-33. [20] Furthermore,w hen CO 2 is introduced, the EPR signal of BIF-29 exhibit slightly changed with irradiation time,s uggesting that the trapped electrons on Cu sites can be further transferred to the adsorbed CO 2 molecules on the catalytic sites.…”