title: Gas sensing properties of MWCNT layers electrochemically decorated with Au and Pd nanoparticles.
abstract: Multiwalled carbon nanotube (MWCNT)-based chemiresistors were electrochemically decorated with Au and Pd nanoparticles (NPs), resulting in an improvement in the detection of gaseous pollutants as compared to sensors based on pristine MWCNTs. Electrophoresis was used to decorate MWCNTs with preformed Au or Pd NPs, thus preserving their nanometer-sized dimensions and allowing the metal content to be tuned by simply varying the deposition time. The sensing response of unmodified and metal-decorated MWCNTs was evaluated towards different gaseous pollutants (e.g., NO2, H2S, NH3and C4H10) at a wide range of concentrations in the operating temperature range of 45-200 °C. The gas sensing results were related to the presence, type and loading of metal NPs used in the MWCNT functionalization. Compared to pristine MWCNTs, metal-decorated MWCNTs revealed a higher gas sensitivity, a faster response, a better stability, reversibility and repeatability, and a low detection limit, where all of these sensing properties were controlled by the type and loading of the deposited metal catalytic NPs. Specifically, in the NO2gas sensing experiments, MWCNTs decorated with the lowest Au content revealed the highest sensitivity at 150 °C, while MWCNTs with the highest Pd loading showed the highest sensitivity when operated at 100 °C. Finally, considering the reported gas sensing results, sensing mechanisms have been proposed, correlating the chemical composition and gas sensing responses.
authors.affiliation: Department of Chemistry, Università degli Studi di Bari Aldo Moro, Bari, Italy; Department of Electrotechnics and Electronics, Politecnico di Bari, Bari, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Dilonardo
authors.affiliation: Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Laboratory Functional Materials and Technologies for Sustainable Applications - Brindisi Research Center, Brindisi, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Penza
authors.affiliation: Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Laboratory Functional Materials and Technologies for Sustainable Applications - Brindisi Research Center, Brindisi, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Alvisi
authors.affiliation: Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Laboratory Functional Materials and Technologies for Sustainable Applications - Brindisi Research Center, Brindisi, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Rossi
authors.affiliation: Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Laboratory Functional Materials and Technologies for Sustainable Applications - Brindisi Research Center, Brindisi, Italy.
authors.forename: Gennaro
authors.initials: G
authors.lastname: Cassano
authors.affiliation: CNR-IFN Bari, Bari, Italy.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Di Franco
authors.affiliation: Department of Chemistry, Università degli Studi di Bari Aldo Moro, Bari, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Palmisano
authors.affiliation: Department of Chemistry, Università degli Studi di Bari Aldo Moro, Bari, Italy.
authors.forename: Luisa
authors.initials: L
authors.lastname: Torsi
authors.affiliation: Department of Chemistry, Università degli Studi di Bari Aldo Moro, Bari, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Cioffi
keywords: Au nanoparticle; Pd nanoparticle; chemiresistive gas sensor; electrophoretic deposition; electrosynthesis; metal-functionalized MWCNTs