Red-blood-cell like nitrogen-doped carbons with highly catalytic activity towards oxygen reduction reaction

Effects of N mono- and N/P dual-doping on H2O2, OH generation, and MB electrochemical degradation efficiency of activated carbon fiber electrodes

Pure N mono- and N/P dual-doped cotton-stalk-derived activated carbon fibers (CSCFs) were synthesized by steam, HNO₃(CSCF-N), NH₃(CSCF-A), and (NH₄)₃PO₄(CSCF-N/P) treatments. This study investigated how three different N/P modifiers affected the pore structure, chemical property, H₂O₂ generation ability, and electrocatalytic activity of methylene blue (MB) degradation of CSCFs in an electric-Fenton system. Results confirmed that the three employed treatments effectively doped N/P in the carbon lattice and slightly changed the pore structures. NH₃ and (NH₄)₃PO₄ were the most effective modifiers for the N mono-doping and N/P dual-doping of CSCFs, respectively. Among the fabricated CSCFs, the N/P dual-doped CSCF-N/P demonstrated the highest electrochemical activity in an electro-Fenton system, followed by the N mono-doped CSCF-A, the CSCF-N, and the raw CSCF. In contrast to the CSCF electrode, the CSCF-N/P electrode exhibited enhanced H₂O₂, OH generation, and MB degradation efficiency by 42%, 41%, and 35%, respectively. Under optimum conditions, the electrochemical decolorization efficiency of MB (initial concentration, 100 mg L^-1) of the CSCF-N/P reached 93% after 150 min and was 24.1% higher than that of the CSCF. By the tenth cycle, 82.2% of the MB could still be decomposed, suggesting the excellent stability and reusability of the N/P co-doped CSCF electrode. The outstanding electrocatalytic performance of the CSCF-N/P electrode is primarily due to the simultaneous doping of active N/P sites with low activation energy and introduction of mesopores with strong trapping forces for MB. The MB reduction catalyzed by CSCF electrodes followed pseudo-first-order kinetics, and the reaction rate depended on the modifiers.

In situ formed Fe–N doped metal organic framework@carbon nanotubes/graphene hybrids for a rechargeable Zn–air battery

An in situ route to produce Fe–N doped metal organic framework@carbon nanotubes/graphene hybrids was proposed. The composite exhibits exceptionally high performances in rechargeable Zn–air batteries.