Nanocasting SiO<sub>2</sub> into metal-organic frameworks imparts dual protection to high-loading Fe single-atom electrocatalysts.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32504040.
- Also identified by DOI 10.1038/s41467-020-16715-6 and PMC identifier 7275045.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Single-atom catalysts (SACs) have sparked broad interest recently while the low metal loading poses a big challenge for further applications. Herein, a dual protection strategy has been developed to give high-content SACs by nanocasting SiO<sub>2</sub> into porphyrinic metal-organic frameworks (MOFs). The pyrolysis of SiO<sub>2</sub>@MOF composite affords single-atom Fe implanted N-doped porous carbon (Fe<sub>SA</sub>-N-C) with high Fe loading (3.46 wt%). The spatial isolation of Fe atoms centered in porphyrin linkers of MOF sets the first protective barrier to inhibit the Fe agglomeration during pyrolysis. The SiO<sub>2</sub> in MOF provides additional protection by creating thermally stable FeN<sub>4</sub>/SiO<sub>2</sub> interfaces. Thanks to the high-density Fe<sub>SA</sub> sites, Fe<sub>SA</sub>-N-C demonstrates excellent oxygen reduction performance in both alkaline and acidic medias. Meanwhile, Fe<sub>SA</sub>-N-C also exhibits encouraging performance in proton exchange membrane fuel cell, demonstrating great potential for practical application. More far-reaching, this work grants a general synthetic methodology toward high-content SACs (such as Fe<sub>SA</sub>, Co<sub>SA</sub>, Ni<sub>SA</sub>).