Cobalt-Based Nitride-Core Oxide-Shell Oxygen Reduction Electrocatalysts

Abstract

Developing high-performance, low-cost, and conductive nonprecious electrocatalysts for the oxygen reduction reaction (ORR) has been a key challenge for advancing fuel cell technologies. Here, we report on a novel family of cobalt nitrides (Co x N/C, x = 2, 3, 4) as ORR electrocatalysts in alkaline fuel cells. Co 4 N/C exhibited the highest ORR activity among the three types of cobalt nitrides studied, with a half-wave potential (E 1/2 ) of 0.875 V vs RHE in 1 M KOH, rivaling that of commercial Pt/C (0.89 V). Moreover, Co 4 N/C showed an 8-fold improvement in mass activity at 0.85 V, when compared to cobalt oxide, Co 3 O 4 /C, and a negligible degradation (ΔE 1/2 = 14 mV) after 10 000 potential cycles. The superior performance was ascribed to the formation of a conductive nitride core surrounded by a naturally formed thin oxide shell (about 2 nm). The conductive nitride core effectively mitigated the low conductivity of the metal oxide, and the thin oxide shell on the surface provided the active sites for the ORR. Strategies developed herein represent a promising approach for the design of other novel metal nitrides as electrocatalysts for fuel cells.

Dynamic electrocatalyst with current-driven oxyhydroxide shell for rechargeable zinc-air battery

“…1c, d). The clear boundary inbetween verifies the critical role of a thin carbon layer in improving the air stability of nitride and protecting it from gradual oxidation in air 29,30 . Raman spectroscopy analysis of the sample confirms both graphitic and defective carbon characteristics ( Supplementary Fig.…”

Efficient Water Splitting Actualized through an Electrochemistry‐Induced Hetero‐Structured Antiperovskite/(Oxy)Hydroxide Hybrid

“…[ 18 ] Furthermore, two featured peaks that correspond to the Ni/InN and NH were observed at 397.5 and 399.3 eV in the N 1s spectrum, respectively, confirming the existence of metal‐nitride bonds in the obtained InNNi 3 . [ 19 ] The absence of NO in InNNi 3 antiperovskite relative to Ni 3 N again demonstrates the improved anti‐oxidation ability to air of InNNi 3 .…”

Transition metal/carbon hybrids for oxygen electrocatalysis in rechargeable zinc‐air batteries

“…The synergistic interaction between metal species and heteroatom‐doped carbon promotes excellent catalytic performance of the M‐N‐C catalysts, which is superior to that of noble metal‐based counterparts in both alkaline and acid electrolytes 39‐41 . Furthermore, their intrinsic structures and chemical stability make them highly tolerant of impurities and contaminants over the noble metals ones during ORR and OER process 42‐44 .…”