Double-Layer Carbon Encapsulated Co Particles Combined with Ionic Liquid for Enhancing Electrochemical Detection of Oxygen

Abstract

As one kind of potential electrolyte material, ionic liquids (ILs) have been widely applied in miscellaneous electrochemistry fields because of their good stability, wide electrochemical window, and nonevaporation at room temperature. Even so, limitations such as low conductivity and poor electrochemical performance still remain when they serve as electrolytes for sensors. Herein, the Co-N/C microcube electrochemical catalyst with N-doped carbon confined Co particles was fabricated via precipitation and carbonization methods. The Co-N/C microcube possesses a rich surface area, internal voids, and good electrochemical activity that are conducive to the catalytic performance of oxygen reduction in ionic liquid electrolytes. Co-N/C was mixed with the pure ionic liquid 1-butyl-1methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([C 4 mpyrr]-[TFSI]) to form the composite electrolyte Co-N/C/[C 4 mpyrr][TFSI], and the sensing performance of Co-N/C/[C 4 mpyrr][TFSI] was visibly enhanced compared with [C 4 mpyrr][TFSI]. Noticeably, the optimized composite electrolyte Co-N/C-700/[C 4 mpyrr][TFSI] exhibited excellent oxygen concentration detecting abilities with a sensitivity of 0.1545 μA/[% O 2 ] and a linear correlation of 0.9991 between response current and O 2 concentration in cyclic voltammetry. Meanwhile, chronoamperometry ensured the responsiveness in a wide range of O 2 concentrations from 0 to 100%. This work paves a new way for promoting the oxygen sensing performance including sensitivity, responsibility, and stability of ionic liquid electrolytes by the addition of Co-N/C-700.

In situ creation of a catalytic multiphase and multiscale surroundings for remarkable hydrogen storage performance of MgH2

“…To the best of our knowledge, this is the rst experimental observation on the in situ formation of catalytic active species although similar conclusions have been speculated in the cases of other intermetallic compounds (e.g., ZrMn 2 , ZrCo, TiFe, CeNi 5 , FeCo, and CoNi). [43][44][45][46][47][48] Such changes can be schematically illustrated by Fig. 9 and largely facilitate the improvement of hydrogen storage properties of nano-ZrFe 2 -modied MgH 2 .…”

“…Moreover, a "double hydrogen pump" effect was used to explain the synergistic catalysis between Mg 2 Co and Mg 2 Ni derived from the CoNi@C nanoparticle-modied MgH 2 . 48 Furthermore, the multielement high entropy alloys (HEAs), TiVNbZrFe, TiVNbZrNi, and TiVNbCrNi were also used to improve MgH 2 . The optimal MgH 2 -10 wt% TiVNbZrFe sample started releasing hydrogen at ∼200 °C and the fully desorbed sample absorbed ∼3.3 wt% hydrogen within 120 minutes at room temperature.…”

Highly sensitive light-induced thermoelastic spectroscopy oxygen sensor with co-coupling photoelectric and thermoelastic effect of quartz tuning fork

“…Therefore, it is of great importance to carry out O 2 concentration detection with fast response and high sensitivity. Currently, one of the most widely used O 2 detection methods are electrochemical sensors [4] , [5] . Unfortunately, disadvantages of electrochemical O 2 sensors, such as aging and contamination have limited their application in many fields.…”