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Potassium sulphate (K 2 SO 4 ) activation of chestnut shell to oxygen‐enriched porous carbons with enhanced capacitive properties
Author(s) -
Hong Ping,
Liu Xu,
Zhang Xu,
Peng Sijia,
Zou Tong,
Wang Zidong,
Yang Yue,
Zhao Rongjun,
Chen Yunhua,
Wang Yude
Publication year - 2020
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.5288
Subject(s) - scanning electron microscope , x ray photoelectron spectroscopy , chemical engineering , thermogravimetry , mesoporous material , chemistry , specific surface area , transmission electron microscopy , porosity , differential scanning calorimetry , oxygen , materials science , analytical chemistry (journal) , inorganic chemistry , nanotechnology , organic chemistry , composite material , engineering , physics , thermodynamics , catalysis
Summary Noncorrosive K 2 SO 4 is found to be able to activate the chestnut shell carbon to oxygen‐enriched porous carbons. Chestnut shells are activated by K 2 SO 4 . The structure, texture, chemical state of surface of samples and morphology are analyzed via X‐ray diffraction, X‐ray photoelectron spectroscopy, Raman spectra, transmission electron microscopy and scanning electron microscopy, respectively. With the optimum amount of K 2 SO 4 (m(K 2 SO 4 )/m(C) = 1.8), higher specific surface area (SSA, 1412 m 2 g −1 ) and total pore volume (0.75 m 2 g −1 ) are obtained. The prepared carbon samples exhibit a hierarchical textural structure making up of micropores, mesopores and macropores. More importantly, a large amount of oxygen defects, as high as 37.7%, and a small amount of sulfur element (0.31%‐0.79%) are successfully introduced on the surface of the carbons. The activation mechanism of K 2 SO 4 is also investigated via thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC), which put it down to the high‐temperature redox reaction between C and K 2 SO 4 . Owing to the high SSA, the composition of pore, and the abundant surface defects, the activated porous carbons originated from chestnut shell carbon possess highly enhanced capacitive properties. At 0.1 A/g, the specific capacitance reaches 265 F/g, and retains 92% of its starting value after 10 000 cycles at 10 A/g. In general, K 2 SO 4 is a promising noncorrosive alternative to the conventional KOH activator.