Surface Modification of Multi-Walled Carbon Nanotubes via Hemoglobin-Derived Iron and Nitrogen-Rich Carbon Nanolayers for the Electrocatalysis of Oxygen Reduction

Abstract

The great challenge of boosting the oxygen reduction reaction (ORR) activity of non-noble-metal electrocatalysts is how to achieve effective exposure and full utilization of nitrogen-rich active sites. To realize the goals of high utilization of active sites and fast electron transport, here we report a new strategy for synthesis of an iron and nitrogen co-doped carbon nanolayers-wrapped multi-walled carbon nanotubes as ORR electrocatalyst (N-C@CNT-Fe) via using partially carbonized hemoglobin as a single-source precursor. The onset and half-wave potentials for ORR of N-C@CNT-Fe are only 45 and 54 mV lower than those on a commercial Pt/C (20 wt.% Pt) catalyst, respectively. Besides, this catalyst prepared in this work has been confirmed to follow a four-electron reaction mechanism in ORR process, and also displays ultra-high electrochemical cycling stability in both acidic and alkaline electrolytes. The enhancement of ORR activity can be not only attributed to full exposure and utilization of active site structures, but also can be resulted from the improvement of electrical conductivity owing to the introduction of CNT support. The analysis of X-ray photoelectric spectroscopy shows that both Fe–N and graphitic-N species may be the ORR active site structures of the prepared catalyst. Our study can provide a valuable idea for effective improvement of the electrocatalytic activity of non-noble-metal ORR catalysts.

Transforming Waste Poly(Ethylene Terephthalate) into Nitrogen Doped Carbon Nanotubes and Its Utility in Oxygen Reduction Reaction and Bisphenol-A Removal from Contaminated Water

“…The electrochemical behavior as studied by CV diagrams (Figure 3a) of our newly developed wPET derived Fe@NCNT-rGO was tested in nitrogen and oxygen saturated 0.1 M KOH electrolytes. Irrespective of the saturation, the CV curve has similar shape of our Fe@NCNT-rGO is similar to that of other reported Fe-N containing carbon nano-allotrope electrocatalysts [36][37][38] and the CV curve in oxygen saturated system shows a visually discernible peak at~0.755 V whereas in nitrogen saturated electrolyte this peak is not observed which indicates the our newly developed wPET derived Fe@NCNT-rGO are excellently electro-catalysts for ORR type reactions. The ORR activity and kinetics was studied by linear sweep voltammetry (LSV) tests using a rotating disk electrode (RDE) in an O 2 saturated 0.1 M KOH electrolyte and compared with that of commercially available 20 wt% Pt/C electrodes and plotted in Figure 3b which indicates that Fe@NCNT-rGO exhibits a distinct electrocatalytic ORR activity with a high onset potential of 0.896 V vs. RHE, which is close to the onset potential potential of commercial Pt/C catalyst (0.92 V).…”

Vitamin Derived Nitrogen Doped Carbon Nanotubes for Efficient Oxygen Reduction Reaction and Arsenic Removal from Contaminated Water

“…Therefore, there is a need for alternatives that are based on non-noble metals. Amongst the various alternatives, elements of iron triad, namely iron [1,2], cobalt [3,4] and nickel [5,6], and ntrogen-doped carbon materials [7,8], have been extensively explored as low-cost and high-performance electrocatalysts. Amongst these, iron nano-particles that are embedded in nitrogen doped conductive carbon nanostructures have aroused tremendous interest due to its excellent catalytic activity.…”

Awn Stem-Derived High-Activity Free-Metal Porous Carbon for Oxidation Reduction

“…Oxygen reduction reaction (ORR) is a particularly important part of the new energy storage and conversion devices [ 1 , 2 , 3 ]. However, excessive overpotential and slow kinetics of ORR at the cathode are the main challenges that the realization of a wide range of commercial applications of fuel cells face [ 4 , 5 , 6 , 7 ].…”