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Post‐formation Copper‐Nitrogen Species on Carbon Black: Their Chemical Structures and Active Sites for Oxygen Reduction Reaction
Author(s) -
Xie Xin,
Liu Jingjun,
Li Tuanfeng,
Song Ye,
Wang Feng
Publication year - 2018
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.201801764
Subject(s) - catalysis , x ray photoelectron spectroscopy , carbon black , carbon fibers , x ray absorption spectroscopy , copper , inorganic chemistry , chemistry , nitrogen , transition metal , oxygen , ammonia , absorption spectroscopy , ammonia production , chemical engineering , materials science , organic chemistry , composite number , natural rubber , physics , quantum mechanics , engineering , composite material
The 3d transition metal and nitrogen co‐doped carbon materials (TM‐N‐C) are considered as the most promising next‐generation electrocatalysts, as alternatives to precious Pt, for the oxygen reduction reaction (ORR). Herein, we have fabricated a Cu‐N‐C catalyst through directly grafting copper‐nitrogen complexes, composed by cuprous chloride and ammonia water, onto the surface of carbon black at 500 °C. In an alkaline environment, the synthesized catalyst exhibits excellent ORR catalytic activity, which is comparable to the state‐of‐the‐art Pt/C catalyst, but far exceeding that obtained by the original carbon. Moreover, the catalyst displays much better stability than Pt/C. The enhanced ORR performance is proven to originate from the post‐formation Cu I −N 2 and Cu II −N 4 sites at the carbon surface, as evidenced by X‐ray photoelectron spectroscopy (XPS) and X‐ray absorption spectroscopy (XAS). The possible ORR process catalyzed by these Cu−N x species is discussed at the atomic level. This work provides a simple and fast synthesis strategy for efficient TM‐N‐C catalysts on a large scale for energy storage and conversion systems.