Nanostructured robust cobalt metal alloy based anode electro-catalysts exhibiting remarkably high performance and durability for proton exchange membrane fuel cells

Patel, Prasad Prakash; Datta, Moni Kanchan; Velikokhatnyi, Oleg I.; Jampani, Prashanth H.; Hong, Dae-Ki; Poston, James A.; Manivannan, A.; Kumta, Prashant N.

doi:10.1039/c5ta01362c

Cited by 30 publications

(62 citation statements)

References 85 publications

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“…5a) which is ~56% of that obtained using Pt/C (Pt loading = 0.3 mg Pt /cm 2 ) as the cathode electro-catalyst (~990 mW/cm 2 as reported before by the present authors3). This is indeed a hallmark finding as the DOE recommended power density (~550 mW/cm 2 ) is obtained using the novel noble metal-free electro-catalysts (Cu 1.5 Mn 1.5 O 4 :10F).…”

Section: Resultssupporting

confidence: 79%

“…Thus, to study the inherent electrochemical activity of the electro-catalysts, ohmic resistance (R Ω ) correction (iR Ω = iR s + iR e )234538 has been conducted in the polarization and cyclic voltammogram (CV) curves. The values of R s and R e of the different electro-catalysts are obtained from electrochemical impedance spectroscopy (EIS) measurements (discussed later) and given in Tables 1 and 2.…”

Section: Resultsmentioning

confidence: 99%

“…4d) and the Tafel slope (decrease in the activation polarization3) (Supplementary Fig. S13 and Table 2) with the lowest obtained for Cu 1.5 Mn 1.5 O 4 :10F [~15.6 ± 0.001 Ω.cm 2 , ~68 ± 0.001 mV/dec in low current region (LCR) and ~123 ± 0.001 mV/dec in the high current region (HCR)].…”

Section: Resultsmentioning

confidence: 99%

“…Elemental analysis of the electrolyte was performed after 6000 cycles by inductively coupled plasma optical emission spectroscopy (ICP-OES, iCAP 6500 duo Thermo Fisher) to determine the amount of elements leached out into the electrolyte solution from the electrode providing vital information about the electrochemical stability of the electro-catalyst23.…”

Section: Methodsmentioning

confidence: 99%

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Noble metal-free bifunctional oxygen evolution and oxygen reduction acidic media electro-catalysts

Patel

Datta

Velikokhatnyi

et al. 2016

Sci Rep

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111

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Identification of low cost, highly active, durable completely noble metal-free electro-catalyst for oxygen reduction reaction (ORR) in proton exchange membrane (PEM) fuel cells, oxygen evolution reaction (OER) in PEM based water electrolysis and metal air batteries remains one of the major unfulfilled scientific and technological challenges of PEM based acid mediated electro-catalysts. In contrast, several non-noble metals based electro-catalysts have been identified for alkaline and neutral medium water electrolysis and fuel cells. Herein we report for the very first time, F doped Cu1.5Mn1.5O4, identified by exploiting theoretical first principles calculations for ORR and OER in PEM based systems. The identified novel noble metal-free electro-catalyst showed similar onset potential (1.43 V for OER and 1 V for ORR vs RHE) to that of IrO2 and Pt/C, respectively. The system also displayed excellent electrochemical activity comparable to IrO2 for OER and Pt/C for ORR, respectively, along with remarkable long term stability for 6000 cycles in acidic media validating theory, while also displaying superior methanol tolerance and yielding recommended power densities in full cell configurations.

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Section: Resultssupporting

confidence: 79%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Noble metal-free bifunctional oxygen evolution and oxygen reduction acidic media electro-catalysts

Patel

Datta

Velikokhatnyi

et al. 2016

Sci Rep

Self Cite

111

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“…The PW 12 O 3À 40 group establishes a negative electric field over the catalyst surface that protects complex metal anions from being subjected to electrostatic repulsion so as to conserve the active metal species on the catalyst surface [42]. Thus, the incorporation of HPW can improve the electrical conductivity of Ag@Pt/MWCNTs.…”

Section: Electrochemical Investigationmentioning

confidence: 99%

Synthesis and electrocatalytic performance of phosphotungstic acid-modified Ag@Pt/MWCNTs catalysts for oxygen reduction reaction

Wang

Zhu

et al. 2016

J Appl Electrochem

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Keggin-structured phosphotungstic acid H 3 PW 12 O 40 (HPW)-modified Ag@Pt/MWCNTs electrocatalysts were successfully prepared using a chemical impregnation method. Physical characterization by X-ray powder diffraction, high-resolution transmission electron microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy revealed that the HPW molecules were incorporated into the Ag@Pt/MWCNT structure The diameter of the catalyst used was about 4.0 nm, and electrochemical investigation results indicated that HPW could ameliorate electrocatalytic activity. The catalyst with HPW content of 25 % displayed the best excellent electrocatalytic activity with an electrochemically active area of 83.62 m 2 g -1 and a half-wave potential for the oxygen reduction reaction of 0.851 V, all ascribed to the high utilization of Pt and the protective effect of the HPW layer on the catalyst surface. The synergic effect of the HPW and Ag@Pt enhanced the rate of electron transfer and increased the catalytic efficiency of oxygen reduction reaction, influencing 4e -reduction reactions on Ag@Pt/MWCNTs-HPW catalysts. Graphical AbstractPhosphotungstic acid-modified Ag@Pt/MWCNTs catalysts were successfully synthesized by the chemical impregnation method. The morphology and catalytic performance of the prepared catalysts were investigated, leading to the understanding of catalytic mechanism of the catalyst in acidic medium, especially, the importance of HPW in the hybrid catalysts. The investigation indicated that the hybrid catalyst showed excellent activity toward oxygen reduction. Schematic diagram for mechanism of ORR on Ag@Pt/MWCNTs-HPW nanostructure.

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Tuning the Activity of Carbon for Electrocatalytic Hydrogen Evolution via an Iridium‐Cobalt Alloy Core Encapsulated in Nitrogen‐Doped Carbon Cages

et al. 2018

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Graphene, a 2D material consisting of a single layer of sp -hybridized carbon, exhibits inert activity as an electrocatalyst, while the incorporation of heteroatoms (such as N) into the framework can tune its electronic properties. Because of the different electronegativity between N and C atoms, electrons will transfer from C to N in N-doped graphene nanosheets, changing inert C atoms adjacent to the N-dopants into active sites. Notwithstanding the achieved progress, its intrinsic activity in acidic media is still far from Pt/C. Here, a facile annealing strategy is adopted for Ir-doped metal-organic frameworks to synthesize IrCo nanoalloys encapsulated in N-doped graphene layers. The highly active electrocatalyst, with remarkably reduced Ir loading (1.56 wt%), achieves an ultralow Tafel slope of 23 mV dec and an overpotential of only 24 mV at a current density of 10 mA cm in 0.5 m sulfuric acid solution. Such superior performance is even superior to the noble-metal catalyst Pt. Surface structural and computational studies reveal that the superior behavior originates from the decreased ΔG for HER induced by the electrons transferred from the alloy core to the graphene layers, which is beneficial for enhancing CH binding.

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Nanostructured robust cobalt metal alloy based anode electro-catalysts exhibiting remarkably high performance and durability for proton exchange membrane fuel cells

Abstract: Nanostructured Co1−x(Irx) (x= 0.3, 0.4) exhibits excellent electrochemical activity and stability for HOR in PEMFCs.

Cited by 30 publications

References 85 publications

Noble metal-free bifunctional oxygen evolution and oxygen reduction acidic media electro-catalysts

Noble metal-free bifunctional oxygen evolution and oxygen reduction acidic media electro-catalysts

Synthesis and electrocatalytic performance of phosphotungstic acid-modified Ag@Pt/MWCNTs catalysts for oxygen reduction reaction

Tuning the Activity of Carbon for Electrocatalytic Hydrogen Evolution via an Iridium‐Cobalt Alloy Core Encapsulated in Nitrogen‐Doped Carbon Cages

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