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Preparation of ultrafine manganese dioxide by micro‐impinging stream reactors and its electrochemical properties
Author(s) -
Liu ZhiWei,
Zhang QingCheng,
Wen LiXiong,
Chen JianFeng
Publication year - 2016
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.22404
Subject(s) - micromixing , materials science , capacitance , manganese , electrochemistry , chemical engineering , analytical chemistry (journal) , electrode , nanotechnology , metallurgy , chemistry , chromatography , microfluidics , engineering
Ultrafine manganese dioxide (MnO 2 ) was synthesized by a micro‐impinging stream reactor (MISR) built from commercial T‐junctions and steel micro‐capillaries. The α‐type MnO 2 particles prepared by the MISR were of spherical morphology, ∼120 nm in diameter and ∼200 m 2 · g −1 in specific surface area. The particles were smaller and more uniform than those produced with traditional stirred reactors. It was also found that the morphologies and discharge specific capacitance (SC), examined by cyclic voltammograms (CV) and galvanostatic charge/discharge methods, of the prepared MnO 2 depended strongly on the inlet velocity ( u ), volumetric flow ratio ( q ), and chamber configuration of the MISR. The as‐prepared MnO 2 under optimized conditions had a discharge specific capacitance of ∼211 F · g −1 and showed a capacitance decline of ∼18 % after 1000 cycles. These values were superior to those of particles produced with stirred reactors and further confirmed the intensifying effects on micromixing behaviours of MISRs. Therefore, a MISR with good micromixing performance, short preparation time, and continuous operation will be a promising technology for the preparation of ultrafine particles.