Metallic Organic Framework-Derived Fe, N, S co-doped Carbon as a Robust Catalyst for the Oxygen Reduction Reaction in Microbial Fuel Cells

Abstract

Oxygen reduction reaction (ORR) provides a vital role for microbial fuel cells (MFCs) due to its slow reaction kinetics compared with the anodic oxidation reaction. How to develop new materials with low cost, high efficacy, and eco-friendliness which could replace platinum-based electrocatalysis is a challenge that we have to resolve. In this work, we accomplished this successfully by means of a facile strategy to synthesize a metallic organic framework-derived Fe, N, S co-doped carbon with FeS as the main phase. The Fe/S@N/C-0.5 catalyst demonstrated outstandingly enhanced ORR activity in neutral PBS and alkaline media, compared to that of commercial 20% Pt-C catalyst. Here, we started-up and operated two parallel single-chamber microbial fuel cells of an air cathode, and those cathode catalysts were Fe/S@N/C-0.5 and commercial Pt-C (20% Pt), respectively. Scanning electron microscopy (SEM) elaborated that the Fe/S@N/C-0.5 composite did not change the polyhedron morphology of ZIF-8. According to X-ray diffractometry(XRD) curves, the main crystal phase of the resulted Fe/S@N/C-0.5 was FeS. The chemical environment of N, S, and Fe which are anticipated to be the high-efficiency active sites of ORR for MFCs were investigated by X-ray photoelectron spectroscopic(XPS). Nitrogen adsorption/desorption techniques were used to calculate the pore diameter distribution. In brief, the obtained Fe/S@N/C-0.5 material exhibited a pronounced reduction potential at 0.861 V (versus Reversible Hydrogen Electrode(RHE)) in 0.1M KOH solution and –0.03 V (vs. SCE) in the PBS solution, which both outperform the benchmark platinum-based catalysts. Fe/S@N/C-0.5-MFC had a higher Open Circuit Voltage(OCV) (0.71 V), stronger maximum power density (1196 mW/m2), and larger output voltage (0.47 V) than the Pt/C-MFC under the same conditions.

2D/3D-Shaped Fe0.8Ni0.2S2/ZIF-67 as a Nanozyme for Rapid Measurement of H2O2 and Ascorbic Acid with a Low Limit of Detection

“…A satellite oscillation peak was at 724.8 eV. The peaks at 712.7 and 727.2 eV correspond to Fe–O and Fe 3+ , respectively. , In Figure C, the peaks belong to Ni 2+ , Ni 3+ , and Ni–O and the satellite oscillation at 856.4, 874.2, 878.3, and 863.2 eV, respectively. − Figure D shows the S 2p spectrum with three peaks at 162.9, 164.1, and 168.8 eV corresponding to the S 2 2– in pyrite FeS 2 , sulfur atoms of the intermediate oxidation state, and the SO x group, respectively. , Figure E shows the Co 2p spectrum, in which Co 2+ and a satellite oscillation were found. − Figure F shows the C 1s spectra, in which the C–C, the C–N, and the O–CO bonds are at 284.8, 286.5, and 289.2 eV, respectively. − The bonding energy represents the change in the electronic density of the element. The higher the binding energy means the lower the electronic density .…”

“…49−51 Figure 5D shows the S 2p spectrum with three peaks at 162.9, 164.1, and 168.8 eV corresponding to the S 2 2− in pyrite FeS 2 , sulfur atoms of the intermediate oxidation state, and the SO x group, respectively. 52,53 Figure 5E shows the Co 2p spectrum, in which Co 2+ and a satellite oscillation were found. 54−56 Figure 5F shows the C 1s spectra, in which the C− C, the C−N, and the O−C�O bonds are at 284.8, 286.5, and 289.2 eV, respectively.…”

Recent Progress in Metal-Organic Framework-Derived Chalcogenides (MX; X = S, Se) as Electrode Materials for Supercapacitors and Catalysts in Fuel Cells

“…In addition to its outstanding performance as electrode materials in supercapacitors, MOF-derived transition metal sulfides rendered excellent performance when used as catalysts in Fuel cells. The significance of doping the catalyst with S atoms rather than P or B atoms is that the relatively large size of sulfur atoms creates defects and porous structure that leads to a high surface area, accelerated electron transfer, and oxygen adsorption, hence enhanced ORR performance [80][81][82].…”

“…The high activity was also related to the aforementioned properties of high electrical conductivity and the role of the nitrogen heteroatom [88]. Xiao et al [80] prepared ZIF-8-derived Fe, N, and S co-doped carbon as ORR catalyst in microbial fuel cells (MFCs). The Fe/S@N/C-0.5 catalyst demonstrated improved reduction kinetics, high durability, and excellent methanol tolerance.…”

Integrated Three-Dimensional Carbon Nanopolyhedron/Metal Sulfides: An Efficient Electrocatalyst Toward Oxygen Reduction Reaction

“…Accordingly, more and more scientific research are aimed at the catalysts derived from bimetallic or trimetallic MOFs. This is mainly due to the fact that the introduction of a second metal provides more opportunity to synthesize a larger variety of bimetallic MOFs with a tunable composition and an intrinsic structure compared with monometallic MOFs (Liu et al, 2008;Luo et al, 2019;Zhang et al, 2020). You et al (2015) have proposed bimetal-organic frameworks selfadjusted synthesis of support-free porous Co-N-C catalysts by carbonizing Zn/Co bi-MOFs.…”