Naslov
Magnetic biomass-derived pyrolytic carbon: an advanced electrode material for applications in bioelectrocatalysis and electrochemical sensing
(Magnetic biomass-derived pyrolytic carbon: an advanced electrode material for applications in bioelectrocatalysis and electrochemical sensing)

Autori
Rešetar, Egon ; Iveković, Damir

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
7th Regional Symposium on Electrochemistry SEE & 8th Kurt Schwabe Symposium - Book of Abstracts / Horvat-Radošević, Višnja ; Kvastek, Krešimir ; Mandić, Zoran - Zagreb : International Association of Physical Chemists (IAPC), 2019, 125-125

ISBN
978-953-56942-7-4

Skup
7th Regional Symposium on Electrochemistry for South-East Europe ; 8th Kurt Schwabe Symposium

Mjesto i datum
Split, Hrvatska, 27.05.2019. - 30.05.2019

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
biomass pyrolysis ; magnetic carbon ; bioelectrocatalysis ; sensing

Sažetak
Biomass-derived carbons comprise a large class of structurally and morphologically diverse carbon materials produced by the pyrolytic or hydrothermal carbonization of biomass, most commonly the cellulosic, hemicellulosic or lignocellulosic plant wastes. Due to their good electrical conductivity, mesoporous structure, large specific surface area and tunable surface properties, biomass-derived carbons recently received a considerable interest as advanced and sustainable electrode materials for energy storage applications, electrocatalytic oxygen reduction and hydrogen evolution. Here we report on our recent research focused on development and characterization of magnetic biomassderived pyrolytic carbon materials for applications in bioelectrocatalysis and electrochemical sensing. Pyrolytic carbon samples were prepared by carbonization of waste coffee grounds at 600-850 °C in an inert (N2) atmosphere, in the presence of iron(III) salt as a graphitization catalyst, followed by the acid leaching of iron residues from the solvent-accessible surface of carbon particles. Pyrolytic carbons showing good electrical conductivity, well-developed mesoporosity and high specific surface area of 180-210 m2/g were obtained at pyrolysis temperatures above 700 °C, preferably at 800-850 °C. Structurally, these samples comprised of elongated graphitic nanodomains embedded into the amorphous carbon matrix containing randomly dispersed cementite (Fe3C) nanoparticles of 5-50 nm in size, formed as a by-product of the iron catalyzed graphitization process. Due to the presence of the cementite phase, pyrolytic carbons obtained under the aforementioned conditions exhibited ferromagnetic properties, which allow them to be easily manipulated by means of an external magnetic field. Magnetically active pyrolytic carbon (MPC) was employed as an electrically conductive substrate for immobilization of horseradish peroxidase (HRP), a well-known model redox enzyme that catalyzes the reduction of hydrogen peroxide in the presence of a suitable electron donor or, in the special case of HRP adsorbed on electrode, through the process of direct electron transfer between the electrode and enzyme redox center. HRP-modified MPC was employed for fabrication of porous film-electrodes, which were kinetically characterized under the conditions of direct and mediated bioelectrocatalysis. The obtained results showed that the HRP immobilized on MPC retains its catalytic activity and is able to participate in direct electron transfer at potentials slightly cathodic to the formal potential of the heme(FeIII)/heme(FeII) redox couple of HRP. It was found that the bioelectrocatalytic activity and long-term catalytic stability of electrodes prepared from HRP-modified MPC were significantly higher than the activity and stability of electrodes prepared from HRP immobilized on graphite powder. Since the results of kinetic modelling showed that the kinetic parameters of HRP immobilized on MPC do not differ significantly from the kinetic parameters of HRP immobilized on plain graphite, the observed increase in the performances of bioelectrocatalytic electrodes prepared from HRP-modified MPC can be attributed to the high specific surface area of MPC and the confinement of HRP within the mesopores of MPC, a mean diameter of which was found to be comparable with the size of HRP molecules. Two examples of advanced application of MPC in bioelectrocatalysis that rely on the ferromagnetic properties of MPC were demonstrated, one related to the application of MPC in fabrication of magnetically renewable porous film bioelectrodes and the second related to fabrication of electrochemical paper-based microfluidic sensors. The latter is especially interesting because it was found that MPC-based inks can be focused by means of an inhomogeneous magnetic field, which opens the perspectives for producing electrically conductive and bioelectrocatalytically active patterns on paper substrates without the use of conventional printing tools.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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