Layered Double Hydroxides (LDHs) have general formula [M(II)M(III)(OH)] x+ (A n-a1-xbx2x/n )mH 2 O, where x ranges between 0.2 and 0.5, depending on the nature of the M a and M b metals [1]. These materials are attractive due to their anionic exchange behaviour which makes them useful in several fields, such as catalysis, separation technology, and medicine. When M a (II) is a transition metal, like Ni or Co, undergoing a reversible redox reaction between the oxidised and reduced states, the material displays improved charge transport properties, especially in alkaline solution [2]. For most LDHs applications in the field of electrochemical sensors, it is required to coat a metal or a carbon-based substrate with a stable thin film. Previously, we have described a simple and rapid electrochemical procedure to deposit, with good reproducibility, well adherent thin films of Ni/Al or Co/Al LDHs on conductive surfaces [3]. In this contribution we report two analytical applications of cobalt-based LDH modified Pt electrodes. The former concerns the development of a potentiometric pH sensor, the latter the amperometric detection of salicylic acid (SA). The performances of the coated electrode as pH sensor are summarized in Figure 1. It shows, as a function of time, the recorded potential and the corresponding pH value, simultaneously recorded with a conventional glass electrode, in a dynamic experiment where the pH of a universal buffer solution is increased in the range 5.5-12 by dropwise addition of KOH. The graph highlights the excellent behaviour of the new sensor, as to response time (5 s for all the investigated pH values) and signal stability. The response is linear, with a slope of -76.2 + 0.6 mV/pH in the pH interval between 2 and 14, and does not suffer from memory effects.

ELECTROCHEMICAL SENSORS BASED ON ELECTRODES COATED WITH LAYERED DOUBLE HYDROXIDES / Lorella Guadagnini; Isacco Gualandi; Adriana Mignani; Marco Monti; Erika Scavetta; Domenica Tonelli. - ELETTRONICO. - (2011), pp. o19-019. (Intervento presentato al convegno IV Workshop del Gruppo Sensori della Divisione di Chimica Analitica della Società Chimica Italiana tenutosi a Teramo nel 15/06/2011).

ELECTROCHEMICAL SENSORS BASED ON ELECTRODES COATED WITH LAYERED DOUBLE HYDROXIDES

GUADAGNINI, LORELLA;GUALANDI, ISACCO;MIGNANI, ADRIANA;MONTI, MARCO;SCAVETTA, ERIKA;TONELLI, DOMENICA
2011

Abstract

Layered Double Hydroxides (LDHs) have general formula [M(II)M(III)(OH)] x+ (A n-a1-xbx2x/n )mH 2 O, where x ranges between 0.2 and 0.5, depending on the nature of the M a and M b metals [1]. These materials are attractive due to their anionic exchange behaviour which makes them useful in several fields, such as catalysis, separation technology, and medicine. When M a (II) is a transition metal, like Ni or Co, undergoing a reversible redox reaction between the oxidised and reduced states, the material displays improved charge transport properties, especially in alkaline solution [2]. For most LDHs applications in the field of electrochemical sensors, it is required to coat a metal or a carbon-based substrate with a stable thin film. Previously, we have described a simple and rapid electrochemical procedure to deposit, with good reproducibility, well adherent thin films of Ni/Al or Co/Al LDHs on conductive surfaces [3]. In this contribution we report two analytical applications of cobalt-based LDH modified Pt electrodes. The former concerns the development of a potentiometric pH sensor, the latter the amperometric detection of salicylic acid (SA). The performances of the coated electrode as pH sensor are summarized in Figure 1. It shows, as a function of time, the recorded potential and the corresponding pH value, simultaneously recorded with a conventional glass electrode, in a dynamic experiment where the pH of a universal buffer solution is increased in the range 5.5-12 by dropwise addition of KOH. The graph highlights the excellent behaviour of the new sensor, as to response time (5 s for all the investigated pH values) and signal stability. The response is linear, with a slope of -76.2 + 0.6 mV/pH in the pH interval between 2 and 14, and does not suffer from memory effects.
2011
BOOK OF ABSTRACTS IV Workshop del Gruppo Sensori della Divisione di Chimica Analitica
o19
019
ELECTROCHEMICAL SENSORS BASED ON ELECTRODES COATED WITH LAYERED DOUBLE HYDROXIDES / Lorella Guadagnini; Isacco Gualandi; Adriana Mignani; Marco Monti; Erika Scavetta; Domenica Tonelli. - ELETTRONICO. - (2011), pp. o19-019. (Intervento presentato al convegno IV Workshop del Gruppo Sensori della Divisione di Chimica Analitica della Società Chimica Italiana tenutosi a Teramo nel 15/06/2011).
Lorella Guadagnini; Isacco Gualandi; Adriana Mignani; Marco Monti; Erika Scavetta; Domenica Tonelli
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/395924
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