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Hexagonal La 2 O 3 Nanocrystals Chemically Coupled with Nitrogen‐Doped Porous Carbon as Efficient Catalysts for the Oxygen Reduction Reaction
Author(s) -
Zhao Jing,
Liu Jingjun,
Jin Chun,
Wang Nan,
Wang Feng
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202001288
Subject(s) - catalysis , carbon fibers , calcination , materials science , adsorption , covalent bond , chemical engineering , inorganic chemistry , nanocrystal , oxygen , desorption , nitrogen , nanotechnology , chemistry , composite number , organic chemistry , composite material , engineering
The construction of nano‐scale hybrid materials with a smart interfacial structure, established by using rare earth oxides and carbon as building blocks, is essential for the development of economical and efficient catalysts for oxygen reduction reactions (ORRs). In this work, hexagonal La 2 O 3 nanocrystals on a nitrogen‐doped porous carbon (NPC) derived from crop radish, served as building bricks, are prepared by chemical precipitation and then calcination at elevated temperatures. The obtained La 2 O 3 /NPC hybrid exhibits a very high ORR activity with a half‐wave potential of 0.90 V, exceeding that of commercial Pt/C (0.83 V). Both DFT theoretical and experimental results have verified that the significantly enhanced catalytic performance is ascribed to the formation of the C−O−La covalent bonds between carbon and La 2 O 3 . Through the covalent bonds, electrons can transfer from the carbon to La 2 O 3 and occupy the unfilled e g orbital of the La 2 O 3 phase. This results in the accelerated adsorption of active oxygen and the facilitated desorption of the surface hydroxides (OH ad − ), thereby promoting the ORR over the catalyst.