Fundamental understanding of nitrogen in biomass electrocatalysts for oxygen reduction and zinc-air batteries
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ABSTRACT:
SUBMITTER: Cao Y
PROVIDER: S-EPMC10839687 | biostudies-literature | 2024 Jan
REPOSITORIES: biostudies-literature
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Project description:A novel and facile two-step strategy has been designed to prepare high performance bi-transition-metals (Fe- and Mo-) carbide supported on nitrogen-doped graphene (FeMo-NG) as electrocatalysts for oxygen reduction reactions (ORR). The as-synthesized FeMo carbide -NG catalysts exhibit excellent electrocatalytic activities for ORR in alkaline solution, with high onset potential (-0.09 V vs. saturated KCl Ag/AgCl), nearly four electron transfer number (nearly 4) and high kinetic-limiting current density (up to 3.5 mA cm(-2) at -0.8 V vs. Ag/AgCl). Furthermore, FeMo carbide -NG composites show good cycle stability and much better toxicity tolerance durability than the commercial Pt/C catalyst, paving their application in high-performance fuel cell and lithium-air batteries.
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Project description:Exploiting the natural structures of plants to prepare high-performance carbon-based electrocatalysts is highly desirable. Herein, the inherently hierarchical microstructures of Euphorbia tirucalli (E. tirucalli) are employed to construct three-dimensional nanoporous nitrogen-doped carbons that act as efficient and durable electrocatalysts towards the oxygen reduction reaction (ORR). During the preparation process, agar is used in order to reduce the dissipation of nitrogen and to protect the fine structures of E. tirucalli. The as-prepared ORR catalyst, with a high density of pyridinic and graphitic nitrogens, presents a high catalytic activity (onset potential of 0.97 V vs. RHE, half-wave potential of 0.82 V vs. RHE, limiting current density of 5.64 mA cm-2 and Tafel slope of 59 mV dec-1), four-electron pathway, low peroxide yield, long-term stability (current retention of 95.3% after 50 000 s) and strong methanol tolerance in 0.1 M KOH, all superior to the benchmark 20% Pt/C commercial catalyst. This work demonstrates an effective method for the utilization of inherently hierarchical microstructures of plant biomass to make efficient and durable carbon-based metal-free ORR electrocatalysts.
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