Elektrochemiczna modyfikacja wielościennych nanorurek węglowych

• Autorzy: Walczyk M.

Identyfikatory

DOI

10.17512/ios.2016.3.1

Warianty tytułu

EN

Electrochemical modification of multi-walled carbon nanotubes

• Języki publikacji: PL

Abstrakty

PL

Poddano modyfikacji elektrochemicznej (utlenianiu/redukcji) wielościenne nanorurki węglowe. Brak elektrochemicznie aktywnych grup funkcyjnych lub/i aktywności elektrochemicznej powierzchni niemodyfikowanych wielościennych nanorurek węglowych potwierdza kształt zarejestrowanych cyklowoltamperogramów, na których nie zaobserwowano jakichkolwiek prądów faradajowskich, mogących pochodzić od procesów związanych z przeniesieniem elektronu, obserwuje się jedynie procesy pojemnościowe ładowania/ rozładowania powierzchni. Elektrochemiczne utlenianie MWCNT generuje karboksylowe grupy funkcyjne nieaktywne w procesach przeniesienia elektronu, a te z kolei generują efekty pojemnościowe i pseudopojemnościowe faradajowskie. Natomiast redukcja wcześniej utlenionych MWCNT nie usuwa grup funkcyjnych, jednakże zmienia się ich forma, gdyż powstają grupy funkcyjne aktywne elektrochemicznie, uczestniczące w procesach przeniesienia elektronu (np. karbonyle, hydroksyle).

EN

Functionalization of carbon nanotubes is a very important step in their practical use in many fields. Modifications of the chemistry of carbon nanotubes lead to significant changes in the physicochemical (e.g. hydrophilic-hydrophobic properties, acid-base properties), electrochemical and catalytic behavior. Surface oxygen functional groups change the electronic structure of the carbon nanotubes, resulting in the localization of the charge density, which is important in the charge-transfer reactions. In addition, oxygen-functionalized carbon nanotubes can be used as an intermediate to create different connections with metals or their complexes and grafting functionalization by biomolecules or polymers. The unmodified carbon nanotubes (MWCNTs) were subjected to electrochemical processes (oxidation and reduction). After the introduction of oxygen to the cell atmosphere, anodization was carried out by applying a potential of +2.0 V vs. Ag/AgCl (3 M KCl) for 1000 s in 1 M electrolyte solutions of potassium chloride. After electrochemical measurements, the electrodes were reduced in the same electrolyte solution at potential of −2.0 V vs. Ag/AgCl (3 M KCl) for 1000 s. Furthermore, electrochemical behavior of the obtained carbon materials was investigated by cyclic voltammetry using a three-electrode electrochemical cell in an aqueous electrolyte, where the working electrode was a carbon nanotubes sedimentation layer. The shape of the cyclic voltammograms (CVs) of unmodified carbon nanotubes are indicative of capacitive effects, no faradic currents were recorded for the systems tested. The absence of distinctly formed peaks or waves suggests the absence of the functional groups on the surface of the unmodified carbon nanotubes. Oxidative modification of carbon nanotubes causes an increase in the surface concentration of electrochemically inactive functional groups, probably carboxyl moieties (only capacitive and pseudo-capacitive effect). Reductive modification of MWCNTs does not remove the surface oxygen functional groups, however, changes their form, which can be seen on the registered CVs. Oxidation/reduction of hydroxide/ ketone species present on the surface of the reduced MWCNT surface explain the observed, more or less completely formed, overlapping anodic/cathodic peaks. After these modifications, significant changes in the electrochemical behavior was observed. The shape of the current hysteresis recorded (magnitude, peaks or waves) strongly depends on the kind of the degree of surface oxidation/reduction. Modification increases the surface concentration of oxygen-containing groups, some of which are electrochemically active in both the capacitive and faradic sense.

Słowa kluczowe

PL

nanorurki węglowe; utlenianie elektrochemiczne; redukcja elektrochemiczna; woltamperometria cykliczna

EN

carbon nanotube; electrochemical oxidation; electrochemical reduction; cyclic voltammetry

• Wydawca: Wydawnictwo Politechniki Częstochowskiej
• Czasopismo: Inżynieria i Ochrona Środowiska
• Rocznik: 2016
• Tom: T. 19, nr 3
• Strony: 297--305
• Opis fizyczny: Bibliogr. 17 poz.

Twórcy

autor

Walczyk M.

• Uniwersytet Mikołaja Kopernika w Toruniu, Wydział Chemii, ul. J. Gagarina 7, 87-100 Toruń

Bibliografia

• [1] Szroeder P., Tsierkezos N.G., Walczyk M., Strupiński W., Górska-Pukownik A., Strzelecki J., Wiwatowski K., Scharff P., Ritter U., Insights into electrocatalytic activity of epitaxial graphene on SiC from cyclic voltammetry and AC impedance spectroscopy, Journal of Solid State Electrochemistry 2014, 1-8.
• [2] Biniak S., Pakuła M., Świątkowski A., Walczyk M., Studies on chemical properties of activated carbon surface, [in:] Carbon Materials - Theory and Practice, eds. A.P. Terzyk, P.A. Gauden, P. Kowalczyk, Research Signpost, Kerala, India 2008.
• [3] Pakuła M., Świątkowski A., Walczyk M., Biniak S., Voltammetric and FTIR studies of modified activated carbon systems with phenol, 4-chlorophenol or 1,4-benzoquinone adsorbed from aqueous electrolyte solutions, Colloids and Surfaces A: Physicochemical and Engineering Aspects 2005, 260, 145-155.
• [4] Pakuła M., Walczyk M., Biniak S., Świątkowski A., Electrochemical and FTIR studies of the mutual influence of lead(II) or iron(III) and phenol on their adsorption from aqueous acid solution by modified activated carbons, Chemosphere 2007, 69, 209-219.
• [5] Świątkowski A., Pakuła M., Biniak S., Walczyk M., Influence of the surface chemistry of modified activated carbon on its electrochemical behaviour in the presence of lead(II) ions, Carbon 2004, 42, 3057-3069.
• [6] Walczyk M., Świątkowski A., Pakuła M., Biniak S., Electrochemical studies of the interaction between a modified activated carbon surface and heavy metal ions, Journal of Applied Electrochemistry 2005, 35, 123-130.
• [7] Choo H.-S., Kinumoto T., Nose M., Miyazaki K., Abe T., Ogumi Z., Electrochemical oxidation of highly oriented pyrolytic graphite during potential cycling in sulfuric acid solution, Journal of Power Sources 2008, 185, 740-746.
• [8] Ohmori S., Saito T., Electrochemical durability of single-wall carbon nanotube electrode against anodic oxidation in water, Carbon 2012, 50, 4932-4938.
• [9] Wang H.J., Yin G.P., Shao Y.Y., Wang Z.B., Gao Y.Z., Electrochemical durability investigation of single-walled and multi-walled carbon nanotubes under potentiostatic conditions, Journal of Power Sources 2008, 176, 128-131.
• [10] Pakuła M., Świątkowski A., Biniak S., Electrochemical behaviour of modified activated carbons in aqueous and nonaqueous solutions, Journal of Applied Electrochemistry 1995, 25, 1038-1044.
• [11] Bandosz T.J., Ania C.O., Surface chemistry of activated carbons and its characterization, [in:] Activated Carbon Surfaces in Environmental Remediation, ed. T.J. Bandosz, Elsevier, New York, USA 2006.
• [12] Basova Y.V., Hatori H., Yamada Y., Miyashita K., Effect of oxidation-reduction surface treatment on the electrochemical behavior of PAN-based carbon fibers, Electrochemistry Communications 1999, 1, 540-544.
• [13] Frysz C.A., Chung D.D.L., Improving the electrochemical behavior of carbon black and carbon filaments by oxidation, Carbon 1997, 35, 1111-1127.
• [14] Chu X., Kinoshita K., Surface modification of carbons for enhanced electrochemical activity, Materials Science and Engineering: B 1997, 49, 53-60.
• [15] Bolzán A.E., Arvia A.J., Electrochemical behavior of carbon materials, [in:] Adsorption by Carbons, eds. E.J. Bottani, J.M.D. Tascón, Elsevier, Amsterdam 2008.
• [16] Świątkowski A., Pakuła M., Biniak S., Cyclic voltammetric studies of chemically and electrochemically generated oxygen species on activated carbons, Electrochimica Acta 1997, 42, 1441-1447.
• [17] Kinoshita K., Carbon: Electrochemical and Physicochemical Properties, John Wiley and Sons, New York 1988.

Uwagi

Opracowanie ze środków MNiSW w ramach umowy 812/P-DUN/2016 na działalność upowszechniającą naukę.