Highly defective carbon nanotubes for sensitive, low-cost and environmentally friendly electrochemical H2O2 sensors: Insight into carbon supports.

We employed the oxidative dehydrogenation of C 2 H 2 by CO 2 and the C 2 H 2 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 C 2 H 2 –CO 2 reaction exhibits superior electrochemical reactivity with H 2 O 2 when compared to the ones with CNTs synthesized via C 2 H 2 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 μA mM−1 cm−2), wide linear working range (5 μM–23 mM), low detection limit (0.138 μM), good selectivity, reproducibility, and stability. The CNTs synthesized via the C 2 H 2 –CO 2 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 H 2 O 2 detection. Image 1 [ABSTRACT FROM AUTHOR]