Promotion of Nitrogen Reserve and Electronic Regulation in Bamboo-like Carbon Tubules by Cobalt Nanoparticles for Highly Efficient ORR

Abstract

N-doped carbon materials are the promising oxygen reduction reaction (ORR) electrocatalyst for many energy systems such as fuel cells and metal−air batteries. Here we report a facile method to regulate electronic structures of bamboo-like carbon tubules dually by rich N-doping and Co particles decoration via pyrolysis of HNO 3 -treated melamine with Co(OH) 2 nanoparticles in an Ar environment (Co-NC-T). XRD, XAFS, and Raman spectra indicate the abundant decoration of metal Co rather than CoO x , and XPS spectra confirm the rich N-doping (7.6%) and abundant Co-NC sites in Co-NC-700, which shows superior ORR activities in 0.1 M KOH with the onset potential of 0.95 V, half-wave potential of 0.90 V, good stability, and methanol tolerance ability. The deformation charge density and adsorption energies (DFT) indicate the dual electronic regulations by N-doping and metal Co can significantly accelerate O 2 adsorption and improve conductivity, which are beneficial for ORR performance of carbon materials. This work provides a facile method to obtain highly active carbon materials via the electronic regulation for efficient catalysis.

Bamboo‐Like Nanozyme Based on Nitrogen‐Doped Carbon Nanotubes Encapsulating Cobalt Nanoparticles for Wound Antibacterial Applications

“…X‐ray photoelectron spectrometer (XPS) was used to analyze the element composition and chemical state in N‐CNTs@Co. As shown in Figure 2B, the Co 2p spectrum was fitted with four peaks, and 794.6 and 778.2 eV were related to Co 2p 1/2 and Co 2p 3/2 , respectively, [ 16 ] suggesting that there was zero‐valent cobalt in N‐CNTs@Co. [ 17 ] In addition, there were two characteristic satellite peaks at 804.6 and 780.1 eV. The N spectrum was divided into three characteristic peaks, and the peak at 397.6 eV was attributed to CoN x and the other peaks located at 397.8, 400.5, and 402.1 eV corresponding to pyridinic N, pyrrolic N, and graphitic N, respectively (Figure 2C).…”

“…The diffraction peaks located at 17.3°, 24.7°, 35.1°, 39.6°, 49.7°, 52.7°, 56.1°, and 68.0° were attributed to (200), ( 220), (400), (420), ( 440), (600), (620), and (640) planes of CoHCF. [15] As for N-CNTs@Co, the diffraction peaks located at 25.0° corresponded to the (002) plane of graphitic carbon, and 44.7° was matched with (111) plane of Co. X-ray photoelectron spectrometer (XPS) was used to analyze the element composition and chemical state in N-CNTs@Co. As shown in Figure 2B, the Co 2p spectrum was fitted with four peaks, and 794.6 and 778.2 eV were related to Co 2p 1/2 and Co 2p 3/2 , respectively, [16] suggesting that there was zero-valent cobalt in N-CNTs@Co. [17] In addition, there were two characteristic satellite peaks at 804.6 and 780.1 eV. The N spectrum was divided into three characteristic peaks, and the peak at 397.6 eV was attributed to CoN x and the other peaks located at 397.8, 400.5, and 402.1 eV corresponding to pyridinic N, pyrrolic N, and graphitic N, respectively (Figure 2C).…”

CoFe/N, S–C Featured with Graphitic Nanoribbons and Multiple CoFe Nanoparticles as Highly Stable and Efficient Electrocatalysts for the Oxygen Reduction Reaction

“… 22 Co-NC bamboolike carbon tubules (HP-Co-CNs) with core Co nanoparticles surrounded by ordered carbon layers showed superior ORR activities, excellent durability, and resistance to methanol in an alkaline medium. 23 Co-N-C nanofibers embedded with Co nanoparticles were prepared for oxygen reduction with high activity and remarkable durability. 24 Although these papers 22 − 24 have reported that transition metal nanoparticles encapsulated in ordered carbon layers/graphitic carbon/graphene can improve the stability of the catalyst, fewer reports investigated on the growth process and mechanism of transition metal-catalyzed graphitization during the pyrolysis and carbonization process.…”

“…The Co/CoO x @Co/N-graphene hybrid electrocatalyst, where the encapsulated Co/CoO x nanoparticles embed in Co/N-doped mesoporous graphene, demonstrated excellent ORR activity, outstanding long-term durability, and resistance to methanol poisoning . Co-NC bamboolike carbon tubules (HP-Co-CNs) with core Co nanoparticles surrounded by ordered carbon layers showed superior ORR activities, excellent durability, and resistance to methanol in an alkaline medium . Co-N-C nanofibers embedded with Co nanoparticles were prepared for oxygen reduction with high activity and remarkable durability .…”

“…Co-N-C nanofibers embedded with Co nanoparticles were prepared for oxygen reduction with high activity and remarkable durability . Although these papers − have reported that transition metal nanoparticles encapsulated in ordered carbon layers/graphitic carbon/graphene can improve the stability of the catalyst, fewer reports investigated on the growth process and mechanism of transition metal-catalyzed graphitization during the pyrolysis and carbonization process.…”