Graphitic Carbon‐NiCo Nanostructures as Efficient Non‐Precious‐Metal Electrocatalysts for the Oxygen Reduction Reaction

Abstract

Composites of graphitic carbon layers and transition metals or metal alloys have received considerable attention for use as non-precious-metal catalysts for ecofriendly energy devices. In this paper, we report graphitic carbon-supported NiCo alloys (NiCo@GC) that function as non-precious-metal electrocatalysts for the oxygen reduction reaction under alkaline conditions. In particular, we examined the effect of the pyrolysis temperature on the oxygen reduction activity. The catalyst prepared at 600 8C provided an oxygen reduction half-wave potential (E 1/2 ) of 0.81 V -only 10 mV less than that of a commercial Pt/C catalyst (0.82 V) -with the transfer of almost four electrons. Structural and chemical studies indicated that the excellent activity and stability of the NiCo@GC catalysts resulted from the strong interactions between (and the combined effects of) the metal and the carbon, dictated by the annealing temperature.

Supramolecular Iron Complex Formed Between Nitrogen Riched Phenanthroline Derivative and Iron With Improved Oxygen Reduction Activity in Alkaline Electrolyte

“…It was considered that the persistence of the CV curve after repeated cycling directly reflected the stability of the catalyst. As shown in Figure 6C, the reduction current density is approximately decreased by 2.3% after 500 cycles, thus a conclusion could be reached that the Fe-PIPhen/C catalyst has good electrochemical stability (Sivanantham and Shanmugam, 2018).…”

Metal–Organic Framework‐Derived Nickel/Cobalt‐Based Nanohybrids for Sensing Non‐Enzymatic Glucose

“…Likewise, the presence of Ni2p 3/2 and Ni2p 1/2 (854.9 eV and 873.8 eV, respectively) with two ”saturation“ peaks (859.8 eV and 878.9 eV) confirms the presence of Ni with oxidation potential [40] . Compared with the Co2p 3/2 and Co2p 1/2 peaks of the original NiCo‐MOF, the Co2p 3/2 and Co2p 1/2 peaks of the NiCo and NiCo/C shifted to the right, which indicates that the electronic structure changed as a result of Ni doping [58,59] . Under a nitrogen atmosphere at high temperatures, the organic ligands directly decompose to graphitized carbon, and some of them may effectively reduce Co 2+ and Ni 2+ to produce metallic Co and Ni.…”

“…[40] Compared with the Co2p 3/2 and Co2p 1/2 peaks of the original NiCo-MOF, the Co2p 3/2 and Co2p 1/2 peaks of the NiCo and NiCo/C shifted to the right, which indicates that the electronic structure changed as a result of Ni doping. [58,59] Under a nitrogen atmosphere at high temperatures, the organic ligands directly decompose to graphitized carbon, and some of them may effectively reduce Co 2 + and Ni 2 + to produce metallic Co and Ni. However, in a H 2 /N 2 atmosphere, the organic ligands may combine before H 2 during the decomposition process, resulting in some of the Co 2 + and Ni 2 + being reduced to metallic Co and Ni.…”

A Review of Carbon‐Supported Nonprecious Metals as Energy‐Related Electrocatalysts

“…The introduction of another/multiple metal(s) into a given metal lattice is expected to modify the electrochemical properties with the ligand and strain effect originating from the formation of heteroatom bonds and the alteration of the bond length. Various carbon‐supported bimetallic and trimetallic nanoparticles, such as NiFe, [ 78 ] FeCu, [ 79 ] and NiCoFe [ 77b ] have been reported. Among various bimetallic compositions, NiFe seems particularly promising.…”