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Chuanlai Jiao Zian Xu Jingze Shao Yu Xia Jochi Tseng Guangyuan Ren Nianji Zhang Pengfei Liu Chongxuan Liu Guangshe Li Shi Chen Shaoqing Chen Hsing-Lin Wang 《Advanced functional materials》2023,33(20):2213897
Developing low-cost single-atom catalysts (SACs) with high-density active sites for oxygen reduction/evolution reactions (ORR/OER) are desirable to promote the performance and application of metal–air batteries. Herein, the Fe nanoparticles are precisely regulated to Fe single atoms supported on the waste biomass corn silk (CS) based porous carbon for ORR and OER. The distinct hierarchical porous structure and hollow tube morphology are critical for boosting ORR/OER performance through exposing more accessible active sites, providing facile electron conductivity, and facilitating the mass transfer of reactant. Moreover, the enhanced intrinsic activity is mainly ascribed to the high Fe single-atom (4.3 wt.%) loading content in the as-synthesized catalyst.Moreover, the ultra-high N doping (10 wt.%) can compensate the insufficient OER performance of conventional Fe N C catalysts. When as-prepared catalysts are assembled as air-electrodes in flexible Zn–air batteries, they perform a high peak power density of 101 mW cm−2, a stable discharge–charge voltage gap of 0.73 V for >44 h, which shows a great potential for Zinc–air battery. This work provides an avenue to transform the renewable low-cost biomass materials into bifunctional electrocatalysts with high-density single-atom active sites and hierarchical porous structure. 相似文献
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Zhonghao Wan Yang Cao Zibo Xu Xiaoguang Duan Shuguang Xu Deyi Hou Shaobin Wang Daniel C.W. Tsang 《Advanced functional materials》2023,33(12):2212227
Copper/carbon catalysts under different electron-transfer regimes can evolve both radical and nonradical pathways in peroxide activation. However, the underlying trigger to manipulate the transition in between is unclear. Herein, it is revealed that Cu species in a state of sub-nanometre particles (SNPs, < 1 nm) exhibits an electrophilic nature, which is opposite to its nucleophilic nature at a larger scale (nanoclusters, > 1 nm). This switch between nucleophile/electrophile nature leads to distinct catalytic mechanisms in activating peroxymonosulfate, i.e., nonradical 1O2 surface-bound upon Cu SNPs and unleashed radical •OH induced by Cu nanoclusters. The vacancy defects of biomass-derived carbon can stabilize Cu SNPs via a Cu V C configuration, circumventing the contemporary difficulties in coordinating/preserving Metal N C bonding. Depth profiling, chemical probes, and charge density difference modeling support the regulable electroactive nature over modulated Cu scales. This featured system is applied for tetracycline degradation, and Cu SNPs demonstrates the highest efficacy with their better peroxymonosulfate confinement in nonradical regime (88.9% removal, nucleophilic activation). Comparatively, severe Cu leaching caused by radical erosion (44.8% removal, electron-donation) is undesirable. Overall, a regulable heterogeneous catalysis is unraveled over carbon-supported Cu sites through scaling modulation and defect engineering. This study illuminates a promising path for customizing biomass-derived Cu-based catalysts to achieve versatile catalysis. 相似文献