Iron Carbide Nanoparticles Supported by Nitrogen-Doped Carbon Nanosheets for Oxygen Reduction

Abstract

Collocation of a suitable catalyst and support is a classic way to tune the activity and stability of catalysts. Herein, we designed a self-sacrificial reagent-directed route to synthesize iron carbide nanoparticles inlaid in a N-doped carbon nanosheet (Fe3C–N–C). With the introduction of the sacrificial reagent, the chemical Fe–N bonds in Fe3C–N–C increases and the size of Fe3C becomes smaller, further leading to uniform dispersion. With the increase of chemical Fe–N bonds, Fe3C–N–C ensures structural stability and prevents surface poisoning and agglomeration. Notably, the Fe3C–N–C catalyst exhibits much higher oxygen reduction reaction activity (E 0 = 0.94 V, E 1/2 = 0.82 V), longer stability (ΔE = −15 mV), and better methanol tolerance than 20% Pt/C (E 0 = 0. 98 V, E 1/2 = 0.85 V, ΔE = −27 mV). Fe3C–N–C materials can also be assembled into Li–O2 batteries taking advantage of their large discharge capacity and excellent cycling stability. Our findings guide in designing advanced carbon-supported metal catalysts.

Unravelling the role of iron carbide in oxygen reduction catalysts for rechargeable zinc–air batteries: a comprehensive kinetics & mechanistic study

“…35-0772) have been compared with those of the synthesised composites. 20 All the synthesised materials (before the acid-washing step) show a characteristic peak at 45°, which corresponds to the bulk Fe particles (JCPDS-06-0696) formed along with the Fe 3 C nanoparticles (Fig. S1†).…”

“…Linear sweep voltammetry before and aer the durability cycles was performed at 1600 rpm rotational speed in O 2 -saturated 0.1 M KOH electrolyte (scan rate is 10 mV s −1 ). 20 All the synthesised materials (before the acid-washing step) show a characteristic peak at 45°, which corresponds to the bulk Fe particles (JCPDS-06-0696) formed along with the Fe 3 C nanoparticles (Fig. S1 †).…”

“…The synthesis of Fe 3 C from various precursors and their ORR activity were reported elsewhere. 15,[17][18][19][20][21][22][23][24][25][26] Nevertheless, most reported materials were synthesised from Fe and nitrogen-containing precursors and denoted as Fe 3 C@N-C, Fe@Fe 3 C/Fe-N x , Fe 3 C/Fe-N x , etc. In these catalysts, the origin of the ORR activity is not only from the Fe 3 C sites but also from the Fe-N x and N-C active sites formed during the process.…”