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Accelerating the oxygen reduction reaction via a bioinspired carbon‐supported zinc electrocatalyst
Author(s) -
Nahavandi Faezeh,
Seyyedi Behnam
Publication year - 2019
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.201800414
Subject(s) - electrocatalyst , tafel equation , chemistry , catalysis , electrochemistry , reversible hydrogen electrode , rotating disk electrode , carbon fibers , zinc , sulfur , inorganic chemistry , oxygen , electrode , chemical engineering , composite number , working electrode , cyclic voltammetry , composite material , materials science , organic chemistry , engineering
Oxygen utilization in electrochemical energy generation systems requires to overcome the slow kinetics of oxygen reduction reaction (ORR). Herein, we have outstretched an efficient strategy in order for developing a bioinspired Zn (N 4 )/sulfur/graphitic carbon composite (Zn‐S‐Gc) with an effective performance for the ORR at low temperature. The catalyst composite was created by attaching the Zn (N 4 ) centers in the form of zinc phthalocyanine on the sulfur‐linked graphitic carbon surface. The most positive ORR onset potential of about 1.00 V versus a reversible hydrogen electrode (RHE) was obtained due to the unique structure of a new catalyst in KOH solution (pH = 13) at low temperature ( T = 298 K). The catalyst was evaluated using the rotating‐disk electrode method in the potential range of −0.02–1.18 V versus RHE. The number of transferred electrons as one of the most important parameters ( n > 3.70) is almost constant in a wide range of low overpotentials (0.1–0.6 V), which indicates a more efficient four‐electron pathway from O 2 to H 2 O on the catalyst surface. The estimated Tafel slope in an appropriate range is about ≈ −133.3 mV/dec at a low current density and E 1/2 of the electrocatalyst displays a negative shift of only 11 mV after 10,000 cycles. The mean size of the catalyst centers is on the nanoscale (<50 nm).