Hydrogen sensing ability at room temperature of bucky-papers based on palladium nanoparticles and multi-walled carbon nanotubes.

A. L. CUKIERMAN; D. ZILLI; P. R. BONELLI

Tel Aviv

Congreso; NanoIsrael 2012 The 3rd International Conference & Exhibition; 2012

Kenes Exhibitions

H2 sensing ability at room temperature of bucky-papers built of pristine and oxidized multiwalled carbon nanotubes (MWCNTs) and Pd metallic nanoparticles is examined. The MWCNTs are lab-synthesized by floating catalyst chemical vapor deposition using iron (II) phtalocyanine and pre-established conditions (895 ºC, total gas flow rate of 30 cm3/min, H2 molar fraction of 0.5, and reaction time of 90 min). Oxidation of the MWCNTs is carried out in an O2  atmosphere (O2 molar raction of 0.10) at 375 ºC for 90 min, using the set-up employed for the synthesis. The bucky-papers are prepared by reduction of mixtures of both pristine and oxidized MWCNTs and PdCl2 solution (1mg/mL), and subsequent filtration of  aqueous suspensions of the Pd decorated MWCNTs. Their sensing ability is determined from measurements of electrica resistance changes when they are exposed to Ar/H2 environment, using a standard four-probe method. Scanning electron microscopy shows that the bucky-papers are 2D structures constituted by randomly oriented MWCNTs. The bucky-papers based on both the pristine and oxidized MWCNTs exhibit reversible responses towards H2, with repeatable characteristics after three sensing cycles (Figure 1). However, the response of the Pd-oxidized MWCNTs based bucky-papers is twice larger, likely because the surface functionalities generated during oxidation could act as anchor seeds for Pd nanoparticles deposition. Their sensing behavior is further investigated for  different H2 average concentrations (70-2100 ppm). The sensor magnitude of response reaches a saturation-like state with a maximum associated value of 2.15% above 350 ppm with short recovery time. Accordingly, the bucky-papers based on the Pd-decorated oxidized MWCNTs have potentialities as room temperature H2 nano-sensors.2 sensing ability at room temperature of bucky-papers built of pristine and oxidized multiwalled carbon nanotubes (MWCNTs) and Pd metallic nanoparticles is examined. The MWCNTs are lab-synthesized by floating catalyst chemical vapor deposition using iron (II) phtalocyanine and pre-established conditions (895 ºC, total gas flow rate of 30 cm3/min, H2 molar fraction of 0.5, and reaction time of 90 min). Oxidation of the MWCNTs is carried out in an O2  atmosphere (O2 molar raction of 0.10) at 375 ºC for 90 min, using the set-up employed for the synthesis. The bucky-papers are prepared by reduction of mixtures of both pristine and oxidized MWCNTs and PdCl2 solution (1mg/mL), and subsequent filtration of  aqueous suspensions of the Pd decorated MWCNTs. Their sensing ability is determined from measurements of electrica resistance changes when they are exposed to Ar/H2 environment, using a standard four-probe method. Scanning electron microscopy shows that the bucky-papers are 2D structures constituted by randomly oriented MWCNTs. The bucky-papers based on both the pristine and oxidized MWCNTs exhibit reversible responses towards H2, with repeatable characteristics after three sensing cycles (Figure 1). However, the response of the Pd-oxidized MWCNTs based bucky-papers is twice larger, likely because the surface functionalities generated during oxidation could act as anchor seeds for Pd nanoparticles deposition. Their sensing behavior is further investigated for  different H2 average concentrations (70-2100 ppm). The sensor magnitude of response reaches a saturation-like state with a maximum associated value of 2.15% above 350 ppm with short recovery time. Accordingly, the bucky-papers based on the Pd-decorated oxidized MWCNTs have potentialities as room temperature H2 nano-sensors.