title: Tuning the Catalytic Activity of a Metal-Organic Framework Derived Copper and Nitrogen Co-Doped Carbon Composite for Oxygen Reduction Reaction.
abstract: An efficient non-noble metal catalyst for the oxygen reduction reaction (ORR) is of great importance for the fabrication of cost-effective fuel cells. Nitrogen-doped carbons with various transition metal co-dopants have emerged as attractive candidates to replace the expensive platinum catalysts. Here we report the preparation of various copper- and nitrogen-doped carbon materials as highly efficient ORR catalysts by pyrolyzing porphyrin based metal organic frameworks and investigate the effects of air impurities during the thermal carbonization process. Our results indicate that the introduction of air impurities can significantly improve ORR activity in nitrogen-doped carbon and the addition of copper co-dopant further enhances the ORR activity to exceed that of platinum. Systematic structural characterization and electrochemical studies demonstrate that the air-impurity-treated samples show considerably higher surface area and electron transfer numbers, suggesting that the partial etching of the carbon by air leads to increased porosity and accessibility to highly active ORR sites. Our study represents the first example of using air or oxygen impurities to tailor the ORR activity of metal and nitrogen co-doped carbon materials and open up a new avenue to engineer the catalytic activity of these materials.
authors.affiliation: Department of Chemistry and Biochemistry, and ‡Department of Materials Science and Engineering, University of California-Los Angeles , Los Angeles, California 90095, United States.
authors.forename: Boris
authors.initials: B
authors.lastname: Volosskiy
authors.affiliation: Department of Chemistry and Biochemistry, and ‡Department of Materials Science and Engineering, University of California-Los Angeles , Los Angeles, California 90095, United States.
authors.forename: Huilong
authors.initials: H
authors.lastname: Fei
authors.affiliation: Department of Chemistry and Biochemistry, and ‡Department of Materials Science and Engineering, University of California-Los Angeles , Los Angeles, California 90095, United States.
authors.forename: Zipeng
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Department of Chemistry and Biochemistry, and ‡Department of Materials Science and Engineering, University of California-Los Angeles , Los Angeles, California 90095, United States.
authors.forename: Stacy
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Chemistry and Biochemistry, and ‡Department of Materials Science and Engineering, University of California-Los Angeles , Los Angeles, California 90095, United States.
authors.forename: Mufan
authors.initials: M
authors.lastname: Li
authors.affiliation: Department of Chemistry and Biochemistry, and ‡Department of Materials Science and Engineering, University of California-Los Angeles , Los Angeles, California 90095, United States.
authors.forename: Zhaoyang
authors.initials: Z
authors.lastname: Lin
authors.affiliation: Department of Chemistry and Biochemistry, and ‡Department of Materials Science and Engineering, University of California-Los Angeles , Los Angeles, California 90095, United States.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Papandrea
authors.affiliation: Department of Chemistry and Biochemistry, and ‡Department of Materials Science and Engineering, University of California-Los Angeles , Los Angeles, California 90095, United States.
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Chemistry and Biochemistry, and ‡Department of Materials Science and Engineering, University of California-Los Angeles , Los Angeles, California 90095, United States.
authors.forename: Yu
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Chemistry and Biochemistry, and ‡Department of Materials Science and Engineering, University of California-Los Angeles , Los Angeles, California 90095, United States.
authors.forename: Xiangfeng
authors.initials: X
authors.lastname: Duan
keywords: electrocatalyst; fuel cell; metal−organic framework; oxygen reduction reaction