Doping Effect on Mesoporous Carbon-Supported Single-Site Bifunctional Catalyst for Zinc–Air Batteries

Abstract

Rechargeable zinc–air batteries (ZABs) require bifunctional electrocatalysts presenting high activity in oxygen reduction/evolution reactions (ORR/OER), but the single-site metal–N–C catalysts suffer from their low OER activity. Herein, we designed a series of single-site Fe–N–C catalysts, which present high surface area and good conductivity by incorporating into mesoporous carbon supported on carbon nanotubes, to study the doping effect of N and P on the bifunctional activity. The additional P-doping dramatically increased the content of active pyridine-N and introduced P–N/C/O sites, which not only act as extra active sites but also regulate the electron density of Fe centers to optimize the absorption of oxygenated intermediates, thereby ultimately improving the bifunctional activity of Fe–N–C sites. The optimized catalyst displayed a half-wave potential of 0.882 V for ORR and a low overpotential of 365 mV at 10 mA cm–2 for OER, which significantly outperforms the counterpart without P, as well as noble-metal-based catalysts. The ZABs with air cathodes containing the N,P-co-doped catalysts exhibited a high peak power density of 201 mW cm–2 and a long cycling stability beyond 600 h. Doping has shown to be an effective way to optimize the performance of single-site catalysts in bifunctional oxygen electrocatalysis, which can be extended to other catalyst systems.

Atomically dispersed Co/Ni dual sites embedded in nitrogen-doped graphene for boosting oxygen evolution

“…[12][13][14][15][16][17] Carbon-based SACs, particularly those with Fe centers (Fe SACs), perform well in ORR. [18][19][20] Nevertheless, the OER abilities of SACs are unsatisfactory because the strong binding energy of electron-donating Page 2 of 17 Energy Advances 3 intermediates and transition metal sites decreases the catalytic behaviors in OER, which is a severe trouble for the achievement of effective OER catalysis. [21,22] To strengthen OER performance, a tactics of heteroatom doping was put forward to construct dual-single-atom (DSA) catalysts by utilizing the complementary functionalities and synergistic effect of two adjacent atomic metal species.…”

Long-Range Regulation of Se Doping for Oxygen Reduction of Atomically Dispersed Sb Catalysts for Ultralow-Temperature Solid-State Zn–Air Batteries

“…Previous investigations indicate that heteroatom doping is usually located in the first shell (bonding with the central atom) or the second shell, ,,− to regulate the electronic distribution of the central atom through short-range regulation, especially for the TM–N–C catalysts. On the contrary, it is often believed that long-range regulation (heteroatoms located in the third shell or more far distance) has no significant effect on the TM central atom due to the far distance.…”

Decoration of NiFe‐LDH Nanodots Endows Lower Fe‐d Band Center of Fe1‐N‐C Hollow Nanorods as Bifunctional Oxygen Electrocatalysts with Small Overpotential Gap

“…has been adopted to optimize the Fe-d band centers of planar Fe-N 4 structure dispersed in carbon lattice, which can effectively regulate the electronic structure and optimize the adsorption strength of intermediate products for boosting the ORR activity. [20][21][22][23][24][25][26] For example, Chen et al report that sulfur doping can induce the transition of spin polarization configuration and lower spin state of the Fe center in Fe 1 -N-C catalysts, which would promote the *OH desorption process. [21] In addition, the intrinsic activities of Fe 1 -N-C catalysts can be also improved by introducing secondary substances including iron clusters [27,28] and MXenes [29] to form various heterostructures.…”