Flower‐like FeS Coated with Heteroatom (S,N)‐Doped Carbon as Highly Active and Durable Oxygen Reduction Electrocatalysts

Abstract

Developing viable substitutes for noble metal electrocatalysts is an important activity, since it enables the movement to a cleaner energy future. Few FeS‐based catalysts have been reported as an oxygen reduction reaction (ORR) catalyst in the past and it does not have the combination of stability, conductivity and reactivity that makes it a viable option. Here, flower‐like FeS covered by ultrathin S,N co‐doped carbon layer (FeS@C) displays outstanding electrocatalytic ORR performance in alkaline media. The optimum FeS@C‐800 sample outperforms undoped commercial FeS and standard Pt/C catalysts with a high positive half‐wave potential (E1/2=0.80 V vs. RHE), high limiting current density (6.4 mA cm−2), complete 4‐electron reduction, superior tolerance to methanol and excellent durability towards ORR. The S,N co‐doped carbon layers could not only enhance the conductivity and durability, but also further contribute to the improvement of ORR activity through synergistic effect with FeS. The FeS@C also promotes performance as the air cathode in a Zn‐air battery, which exhibits higher power density than Pt/C. Hence the reported catalyst holds prospects for use as a high performance electrocatalyst for ORR.

A facile synthesis of FeS/Fe3C nanoparticles highly dispersed on in situ grown N-doped CNTs as cathode electrocatalysts for microbial fuel cells

“…The peaks at 707.14 eV and 720.17 eV correspond to Fe 2+ 2p 3/2 and Fe 2+ 2p 1/2 , respectively, attributed to FeS. The peaks at 710.76 eV and 724.71 eV correspond to Fe 3+ 2p 3/2 and Fe 3+ 2p 1/2 , respectively, belonging to Fe 3 C. 44,50,55 The deconvoluted S 2p spectra of Nano-FeS/Fe 3 C@NCNTs-700 (Fig. 3(i)), Nano-FeS/Fe 3 C@NCNTs-800 (Fig.…”

“…3(g)) displays four peaks at 398.42 eV, 399.79 eV, 401.18 eV and 403.00 eV, corresponding to pyridinic-N, pyrrolic-N, graphitic-N and oxidized-N, respectively. 43,50 Pyridinic-N and graphitic-N are considered as effective doping types to improve the electrocatalytic activity of N-doped carbon materials. 43,51,52 For the oxygen reduction reaction, pyridinic-N can modulate the regional electronic structure of Fe-N-C, driving the ORR toward the ideal four-electron reaction path.…”

Sulfur-Doped Fe–N–C Nanomaterials as Catalysts for the Oxygen Reduction Reaction in Acidic Medium

“…XPS high-resolution spectra for N 1s deconvolution yields four characteristic peaks for both samples, including pyridinic N (398.5 ± 0.2 eV), Fe–N (399.8 ± 0.2), graphitic N (400.9 ± 0.2 eV), and oxidized N (401.9 ± 0.2 eV) (Figure a). Both catalysts possess high pyridinic N content (Table S1), which is believed to contribute to the ORR electrocatalysis. − The percentage of Fe–N increased from 3.0% to 18.5% when thiourea molecules were introduced (Table S1), suggesting that the additional N source provided more coordination to stabilize Fe atoms during thermal activation . The pyridinic N content can also be an extension of Fe–N species, and it has been proven that FeN x species can be formed from the lone-pair electron of pyridinic N that reacts with Fe atoms as an anchor point to form Fe–N species. , The peak corresponding to C–S/C–N for FeN 4 /NSC-1 brings additional evidence of the successful incorporation of S into the graphitic carbon.…”

Heteroatom doped M–N–C single-atom catalysts for high-efficiency oxygen reduction reaction: regulation of coordination configurations

“…To date, a variety of S-doped M–N–C SACs have been successfully prepared, such as S-doped Fe–N–C SACs, 46,47 Ni–N–C SACs, 48 Cu–N–C SACs 49 and Co–N–C SACs. 50 Meanwhile, owing to the novel active structure, these catalysts also show excellent catalytic activity.…”