Highly defective carbon nanotubes for sensitive, low-cost and environmentally friendly electrochemical H2O2 sensors: Insight into carbon supports
Résumé
We employed the oxidative dehydrogenation of C2H2 by CO2 and the C2H2 decomposition to prepare
carbon nanotubes (CNTs) and carbon nanofibers (CNFs). The use of a small amount of Ni catalyst made it
possible to produce CNTs and CNFs having a highly defective structure at a relatively low temperature
compared to the one typically used for the CNT synthesis. The synthesized CNTs and CNFs were decorated
with about 10 nm-gold nanoparticles (AuNPs) via an electrostatic self-attachment. The electrode
with CNTs synthesized via the C2H2eCO2 reaction exhibits superior electrochemical reactivity with H2O2
when compared to the ones with CNTs synthesized via C2H2 decomposition, commercial CNTs, CNFs, and
other more common carbon supports e.g. carbon black and activated charcoal. It demonstrates a rapid
response, high sensitivity (104.9 mA mM1 cm2), wide linear working range (5 mMe23 mM), low
detection limit (0.138 mM), good selectivity, reproducibility, and stability. The CNTs synthesized via the
C2H2eCO2 reaction are suggested as energy-saving, cost-effective and environmentally friendly supporting
material candidates for practical applications. The electrodes with CNTs show a high electrochemically
active surface area, low charge transfer resistance and fast mass transfer at the electrode
surface that are key factors for H2O2 detection.