Noble-Metal-Free Iron Nitride/Nitrogen-Doped Graphene Composite for the Oxygen Reduction Reaction

Abstract

Considerable effort has been devoted recently to replace platinum-based catalysts with their non-noble-metal counterparts in the oxygen reduction reaction (ORR) in fuel cells. Nitrogen-doped carbon structures emerged as possible candidates for this role, and their earth-abundant metal-decorated composites showed great promise. Here, we report on the simultaneous formation of nitrogen-doped graphene and iron nitride from the lyophilized mixture of graphene oxide and iron salt by high-temperature annealing in ammonia atmosphere. A mixture of FeN and Fe 2 N particles was formed with average particle size increasing from 23.4 to 127.0 nm and iron content ranging from 5 to 50 wt %. The electrocatalytic oxygen reduction activity was investigated via the rotating disk electrode method in alkaline media. The highest current density of 3.65 mA cm –2 at 1500 rpm rotation rate was achieved in the 20 wt % catalyst via the four-electrode reduction pathway, exceeding the activity of both the pristine iron nitride and the undecorated nitrogen-doped graphene. Since our catalysts showed improved methanol tolerance compared to the platinum-based ones, the formed non-noble-metal system offers a viable alternative to the platinum-decorated carbon black (Pt/CB) ORR catalysts in direct methanol fuel cells.

Co‐decorated reduced graphene/titanium nitride composite as an active oxygen reduction reaction catalyst with superior stability

“…The result demonstrated a higher ORR activity compared to that of Pt catalyst 67 . Similar results are reported by Varga et al 68 …”

“…The result demonstrated a higher ORR activity compared to that of Pt catalyst. 67 Similar results are reported by Varga et al 68 Though the results of the metal carbides and nitrides are promising, their preparation is not an easy task. 69 The reported method for preparing metal nitrides involves the use of corrosive and highly toxic ammonia gas under high temperature.…”

Surface Reconstruction and Phase Transition on Vanadium–Cobalt–Iron Trimetal Nitrides to Form Active Oxyhydroxide for Enhanced Electrocatalytic Water Oxidation

“…Additionally, there is an emergence of peak in O 1s XPS at 529.0 eV, which is corresponding to peroxo‐like (O 2 2− ) species, and can be only observed after the OER test. [ 20,34 ] From Raman spectra (Figure S22, Supporting Information), most characterized peaks of metal–nitride disappear, [ 10d,35 ] and three distinct peaks are observed that are corresponding to FeOOH [ 36 ] and CoOOH [ 3a,37 ] This result also confirms the phase transition on the surface of CoVFeN@NF in the OER process. In addition, the surface reconstruction and phase transition of the catalyst were further confirmed by the electrochemical test.…”

Mixed Copper/Copper‐Oxide Anchored Mesoporous Fullerene Nanohybrids as Superior Electrocatalysts toward Oxygen Reduction Reaction

“…Another major concern for using any catalyst in real-time direct methanol fuel cells is methanol crossover effect which will reduce the ORR catalytic activity and efficacy of the overall system. [74,75] Hence, we compared the methanol crossover effect between the optimized catalyst (Cu(15%)-MFC 60 ) and the wellknown Pt/C using chronoamperometry by introducing methanol into oxygen saturated 0.1 m KOH electrolyte (Figure 10a). Toward this, the normalized current (I/I o ) (current recorded at a given time to that of the initial current) was compared to that of commercial Pt/C.…”