In Situ Self‐Supporting Cobalt Embedded in Nitrogen‐Doped Porous Carbon as Efficient Oxygen Reduction Electrocatalysts

Abstract

A facile two-step chemical route using cobalt ions coordinated with EDTA (Co II /EDTA chelate complex supported on glucose mixture), followed by the in situ pyrolysis process, from 500 to 900°C, was developed to prepare Co embedded in N-doped porous carbon hybrids (Co@CÀ T). The EDTA chelating agent served as both the N source and pore former. The physicochemical characterization results revealed that the pore structure, graphitization degree, and relative content of active centers, e. g., cobalt-based components and nitrogen species, for Co@CÀ T electrocatalysts, were tailored by controlling the temperature of pyrolysis. The optimized material generated at 600°C (Co@C-600), showed an excellent oxygen reduction reaction activity with an onset potential of 0.91 V vs. RHE, and a half-wave potential of 0.80 V vs. RHE.

Convenient Synthesis of NiCo Alloy Nanoparticles Encapsulated by N-Doped Porous Carbon for the Oxygen Evolution Reaction

“…Moreover, pyridine N and graphite N can effectively improve the conductivity of materials. , As shown in Figure d, there are two peaks located at 853.1 and 856 eV in the Ni 2p spectrum corresponding to the Ni 2p 3/2 orbits of the Ni metallic state and the Ni 2+ oxidation state, respectively. , Peaks of 870.2 and 873.6 eV correspond to the Ni 2p 1/2 orbits of the metallic state and Ni 2+ , respectively, while the two peaks at 860.9 and 879.1 eV are satellite peaks. − The deconvolution of the Co 2p spectrum results in six peaks. The peaks at 778.6 and 796.5 eV belong to the 2p 3/2 and 2p 1/2 orbits of Co 0 , respectively, and the peaks at 781.2 and 796.5 eV belong to the 2p 3/2 and 2p 1/2 orbits of Co 2+ , respectively. − Furthermore, two satellite peaks were observed at 786.5 and 803.5 eV, as shown in Figure e. The partial oxidation of the NiCo alloy is what causes the Ni 2+ and Co 2+ peaks in the XPS analysis.…”