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P. Giri et al.
could have gotten sintered with each other. It is known that PAN has glass transition
temperature (T g ) ~ 80 °C [21], and given that temperature inside cigarette filters can
easily go up to 100 °C [22], it is only possible that some nanofibers have sintered
after attainment of T g . However, visibly their nanofibrous architecture has remained
the same. It was found that electrochemical activity of the membrane carbonized
after filtration was increased, as revealed from CV (Fig. 5a). EDX confirmed the
retention of various transition metals including previously stated Pb, Cr, Fe, and Cd
even after carbonization (Fig. 5b). The presence of these elements is crucial as they
act as dopants, thus increasing electrochemical activities [23].
The samples were oxygen reduction reaction (ORR), hydrogen evolution reaction
(HER), and oxygen evolution reaction (OER) active. The pseudo-capacitance was
increased by 202 % when membranes after cigarette smoke filtration were used as
the test specimens. The specific capacitance was calculated based on the empirical
relation [24]:
c =
ivdv
2μmV
Fig. 5 a Cyclic voltammogram of CNFs prepared after carbonization of PAN membranes. Legends
are embedded in the image; b EDX spectra of CNF obtained from post smoking filters.
P. Giri et al.
could have gotten sintered with each other. It is known that PAN has glass transition
temperature (T g ) ~ 80 °C [21], and given that temperature inside cigarette filters can
easily go up to 100 °C [22], it is only possible that some nanofibers have sintered
after attainment of T g . However, visibly their nanofibrous architecture has remained
the same. It was found that electrochemical activity of the membrane carbonized
after filtration was increased, as revealed from CV (Fig. 5a). EDX confirmed the
retention of various transition metals including previously stated Pb, Cr, Fe, and Cd
even after carbonization (Fig. 5b). The presence of these elements is crucial as they
act as dopants, thus increasing electrochemical activities [23].
The samples were oxygen reduction reaction (ORR), hydrogen evolution reaction
(HER), and oxygen evolution reaction (OER) active. The pseudo-capacitance was
increased by 202 % when membranes after cigarette smoke filtration were used as
the test specimens. The specific capacitance was calculated based on the empirical
relation [24]:
c =
ivdv
2μmV
Fig. 5 a Cyclic voltammogram of CNFs prepared after carbonization of PAN membranes. Legends
are embedded in the image; b EDX spectra of CNF obtained from post smoking filters.