Novel MOF-derived hollow CoFe alloy coupled with N-doped Ketjen Black as boosted bifunctional oxygen catalysts for Zn–air batteries

N-Doped Hollow Carbon Sphere and Polyhedral Carbon Composite Supported Pt/Fe Nanoparticles as Highly Efficient Cathodic Catalysts of Proton-Exchange Membrane Fuel Cells

“…The C 1s peak (Figure e) can be separated into four peaks CC, C–N, CO, and O–CO, , suggesting that N has been successfully doped into the carbon material and formed a strong covalent bond with C. It also can be found that all peaks are consistent except for the CO peak that is positively shifted by 0.54 eV after the addition of Pt, which may be caused by the interaction between Pt and O. For the N 1s XPS spectra (Figure f), both pCN@NHCS-Fe/Pt-280 and pCN@NHCS-Fe show distinct pyridinic N, Fe–N x , pyrrolic N, graphitic N, and oxidized N peaks, while pyridinic N and Fe–N x are the main catalytic centers of the ORR. ,, Furthermore, pyridinic N is considered to be the key factor in the production of the Fe–N x active center, while the formation of Fe–N x also ensures that Fe can be firmly embedded in the structure to prevent the freeing and polymerization of Fe nanoparticles . In addition, the Fe–N x site generates negative electrons, leading to changes in the electronic arrangement of the nearby C, which in turn causes electronic defects in carbon and may favor the embedding of Pt-NPs, and further strengthens the interaction between Fe/Pt and carbon materials. , The deconvolution spectra of the N 1s for the two catalysts allow us to obtain a comparison of the contents of the different N forms, as shown in Figure i.…”

“…The C 1s peak (Figure 3e) can be separated into four peaks C�C, C−N, C�O, and O−C�O, 17,35 suggesting that N has been successfully doped into the carbon material and formed a strong covalent bond with C. It also can be found that all peaks are consistent except for the C�O peak that is positively shifted by 0.54 eV after the addition of Pt, which may be caused by the interaction between Pt and O. For the N 1s XPS spectra (Figure 3f), both pCN@NHCS-Fe/Pt-280 and pCN@ NHCS-Fe show distinct pyridinic N, Fe−N x , pyrrolic N, graphitic N, and oxidized N peaks, 36 while pyridinic N and Fe−N x are the main catalytic centers of the ORR. 17,37,38 Furthermore, pyridinic N is considered to be the key factor in the production of the Fe−N x active center, while the formation of Fe−N x also ensures that Fe can be firmly embedded in the structure to prevent the freeing and polymerization of Fe nanoparticles.…”

Synergies of Atomically Dispersed Mn/Fe Single Atoms and Fe Nanoparticles on N-Doped Carbon toward High-Activity Eletrocatalysis for Oxygen Reduction

“…Recent studies reveal that transition metals encapsulated in N-doped carbonaceous complexes have excellent environmental catalytic activity owing to the synergism between the two components. − Especially, the embedding of transition metals in morphologically diverse carbon is more studied. Appropriate and efficient embedding of transition-metal NPs (NPs) into carbon nanotubes can restrict metal growth and expose enough active sites at the interface, thus improving ORR activity. , Reportedly, reasonably designed bimetallic particles are expected to acquire higher activity and stability than single-metal atomic particles, owing to the interaction of electron clouds and the improved coordination structure stability of the active center. − Moreover, the novel MOF-derived electrocatalyst with FeCo bimetallic active sites encapsulated in N-doped Ketjen Black (CoFe/NC) displays outstanding ORR capability with half-wave potential close to Pt/C (0.845 versus 0.835 V) in a 0.1 M KOH solution . The main reason is that the synergistically structured catalyst can reduce the potential barrier of O–O breaking, resulting in higher ORR activity and efficient four-electron transfer.…”

“…17−19 Moreover, the novel MOFderived electrocatalyst with FeCo bimetallic active sites encapsulated in N-doped Ketjen Black (CoFe/NC) displays outstanding ORR capability with half-wave potential close to Pt/C (0.845 versus 0.835 V) in a 0.1 M KOH solution. 20 The main reason is that the synergistically structured catalyst can reduce the potential barrier of O−O breaking, resulting in higher ORR activity and efficient four-electron transfer. The ideal catalysts to replace commercial Pt-based materials should have multiple O 2 -activating sites, high O−O fracturing ability, an excellent oxygen-diffusion geometric channel structure, and stable active sites, which should all be maintained at high levels for a long term, and they together improve the oxygen reduction-catalyzing potential.…”

Hollow CoFe-based hybrid composites derived from unique S-modulated coordinated transition bimetal complexes for efficient oxygen evolution from water splitting under alkaline conditions

“…29 CoFe alloys are regarded some of the most attractive water-splitting electrocatalysts because they facilitate the transfer of electrons and mass to the active sites of Co and Fe. 30,31 However, most CoFe alloy catalysts have a large particle size, which is disadvantageous in bonding. 32,33 Meanwhile, sulfur doping to carbon materials may facilitate the chemisorption of intermediates and can modify the spin densities during OER due to their larger atomic size.…”