Emanuele Serra | ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development (original) (raw)

Papers by Emanuele Serra

Key Engineering Materials, 2004

In the present study, the resistance to surface abrasion of two commercial glazed ceramic tiles w... more In the present study, the resistance to surface abrasion of two commercial glazed ceramic tiles was determined according to the test method specified in the Standard ISO 10545-7 The worn areas of all the specimens were analysed using a non-destructive technique, an optical profilometer. These results, coupled with a morphological analyses carried out with a scanning electron microscope, allowed to understand the mechanisms acted during the material removal. Germany), equipped with a Vickers indenter at the following indentation loads 1. 95, 2.94, 4.90, 9.81 and 19.62N. At least ten valid impressions for each load were considered.

Advances in Science and Technology, 2006

Si-nanoparticles (NP) are attracting steadily growing interest due to their intriguing sizedepend... more Si-nanoparticles (NP) are attracting steadily growing interest due to their intriguing sizedependent optical properties. The most challenging task in preparing Si-NP is to succeed in controlling the particle size and size distribution and the surface properties. To this respect, the method of laser synthesis of Si-NP from gas phase reactants appears as an ideal tool, being a very versatile and controllable synthesis technique, but the collected Si-NP are strongly agglomerated.

Journal of Solid State Electrochemistry, 2011

This paper reports a study on the understanding of the performance decrease mechanisms of polymer... more This paper reports a study on the understanding of the performance decrease mechanisms of polymer electrolyte fuel cells under critical operating conditions. In order to investigate the durability of perfluorosulfonate membranes at low humidification conditions, long-term fuel cell tests have been carried out. Results evidenced a strong effect of low relative humidity on the commercial polymer membrane lifetime. Prolonged dehydration of the membranes led to a decrease of the three-dimensional reaction zone due to the ionomer degradation in the catalytic layer and a continuous loss of material in the membrane evidenced by a thickness decrease. The last effect provoked a collapse of the electrode structure.

Sensors and Actuators B-chemical, 2010

In this paper the effect of the surface functionalization of the carbon nanotubes (CNT) networked... more In this paper the effect of the surface functionalization of the carbon nanotubes (CNT) networked films with a metalloporphyrins layer is investigated for gas sensing. Modified film exhibits an increased sensitivity of the electrical resistance towards the concentrations of common volatile compounds (alcohols, amines, aromatic and ketones), at room temperature. Furthermore, a part of the adsorption properties of the functional units is transferred to the sensor signal and, as a consequence, the selectivity of the sensor is also modified. Principal Component Analysis (PCA) demonstrates that the functionalization provides enough selectivity change to turn a triplicate of the same CNT film into an effective sensor array capable of the compounds recognition.

Journal of Power Sources, 2008

An electrochemical method for the Pt nanoparticles deposition on porous and high surface carbon s... more An electrochemical method for the Pt nanoparticles deposition on porous and high surface carbon substrates (carbon black and carbon nanotubes), as an alternative way to prepare gas diffusion electrodes for polymer electrolyte fuel cells (PEFCs), is herein described. Pt nanoparticles well distributed and localized on the electrode surface were obtained by using an electric field. The electro-catalysts were prepared by single and multiple pulse galvanostatic polarizations in 1 M sulphuric acid + 5 mM exachloroplatinic acid solution. Chemical analysis, cyclic voltammetry and field emission gun scanning electron microscopy were used to determine the electrochemical features of Pt deposits and the influence of electro-deposition method on their nano-morphology. Electro-catalytic performances were studied by investigating the methanol oxidation reaction and the results are presented in form of surface specific activity and mass specific activity to take into account the electrochemical real surface and Pt loading. A comparison with commercial E-TEK Pt/C catalysts, prepared by traditional chemical reduction and heat treatment in hydrogen, shows that the electrodeposited catalyst presents higher activity at lower Pt loading.

Polymer Electrolyte Fuel Cells (PEFCs) offer low weight and high power density and are being cons... more Polymer Electrolyte Fuel Cells (PEFCs) offer low weight and high power density and are being considered for automotive and stationary power production besides space and electronic applications. In this work, gamma radiation effects on carbon materials (carbon powder and multiwalled carbon nanotubes) used as substrates in PEFCs electrodes, were studied. The enhancing of free radicals formation (especially on carbon powder) was observed and studied by EPR spectroscopy. This evidence leads to a significant activation of carbon materials because paramagnetic sites represent the preferential position for platinum electrocatalyst nucleation. Galvanostatic techniques were applied to deposits platinum nanoparticles on carbon substrates while FEG-SEM characterization and cyclic voltammetry (CV) were carried out to study the morphology and the electrochemical performances of PEFCs electrodes.

Networked carbon nanotubes (CNTs) films have been grown by chemical vapor deposition (CVD) techno... more Networked carbon nanotubes (CNTs) films have been grown by chemical vapor deposition (CVD) technology onto miniaturized Co-coated alumina substrates for NO2 and NH3 gas sensing applications, at a sensor temperature of 150°C. The sidewalls of the CNTs films have been modified by spray-coating with two different metalloporphyrins (MPPs) consisting of a TetraPhenylPorphyrin coordinated by a central metal of zinc (Zn-TPP) and manganese (Mn-TPP) for enhanced sensitivity and tailored specificity. It was demonstrated that the gas sensitivity of the MPPs-modified CNTs-sensors significantly improved by a factor up to four-times through a catalytic effect of the MPPs. The gas sensing properties of CNTs-sensors, including MPPs-modified CNTs, are characterized by a change of the electrical conductivity in a model of charge transfer with a semiconducting p-type character. A response of the CNTs-sensor functionalized with 2 spray-layers of Mn-TPP has been measured as 0.43% to 0.5 ppm NO2, and as 0.09% to 10 ppm NH3, at 150°C. The MPPs-functionalized CNTs-sensors exhibit high sensitivity, fast response, reversibility, good repeatability, sub-ppm range detection limit.

Advances in Science and Technology, 2006

Sensors and Actuators B-chemical, 2008

A gas chemiresistor, fabricated onto alumina using multi-walled carbon nanotubes (MWCNTs) network... more A gas chemiresistor, fabricated onto alumina using multi-walled carbon nanotubes (MWCNTs) networked films grown by radiofrequency plasma enhanced chemical vapor deposition (RF-PECVD) technology, is described for high-performance gas detection, at an operating temperature of 200 • C. Functionalizations of MWCNTs tangled bundle-films with nominally 5-nm thick Pt-and Pd-nanoclusters, prepared by magnetron sputtering, provide higher sensitivity for significantly enhanced gas detection of NO 2 , H 2 S, NH 3 , CO, up to a low limit of sub-ppm level. The measured electrical conductance of the functionalized MWC-NTs upon gas exposures is modulated by charge transfer with p-type semiconducting characteristics. Ptand Pd-nanoclusters functionalized MWCNTs gas sensors exhibited better performances compared to unfunctionalized MWCNTs, making them promising candidates for air-pollutants environmental monitoring. Simple electronic interface for the chemiresistor has been developed with a voltage output of the sensor signal.

Sensors and Actuators B-chemical, 2009

We investigate the impact of the tailored load of gold (Au) nanoclusters functionalizing the side... more We investigate the impact of the tailored load of gold (Au) nanoclusters functionalizing the sidewalls of the carbon nanotubes (CNTs) networks on gas sensing performance of a chemiresistor, operating at a working temperature in the range of 20-250 • C. CNTs networked films have been grown by radiofrequency plasma enhanced chemical vapour deposition (RF-PECVD) technology onto low-cost alumina substrate, provided with 6 nm nominally thick cobalt (Co) growth-catalyst. Nanoclusters of Au have been deposited by sputtering onto CNTs networks with a controlled loading of equivalent thickness of 2.5, 5 and 10 nm. Microstructure and morphology of the CNTs have been characterized by FE-SEM and TEM with diameter of the bundles of nanotubules of 10-40 nm. CNTs and Au-modified CNTs exhibit a p-type response with a decrease in electrical resistance upon exposure to oxidizing NO 2 gas and an increase in resistance upon exposure to reducing gases (NH 3 , CO, N 2 O, H 2 S, SO 2 ). Negligible response has been found for CNTs and Au-modified CNTs sensors exposed to CO, N 2 O, SO 2 . In the contrast, significantly enhanced gas response of NO 2 , H 2 S and NH 3 , up to a low limit of sub-ppm level, has been measured for Au-functionalized CNTs-chemiresistors. Highest gas sensitivity to NO 2 , H 2 S and NH 3 has been found by CNTs functionalized with Au loading of 5 nm, at 200 • C. An optimal operating temperature for each Au-modified CNTs-sensor exposed to NO 2 gas has been recorded. Good repeatability of the electrical response to 200 ppb NO 2 is also reported, at 200 • C. These results demonstrate the efficiency of the CNTs-chemiresistors functionalized with Au nanoclusters for selective air-pollutants environmental monitoring applications.

Procedia Chemistry, 2009

Networked films of carbon nanotubes (CNTs) have been grown by Chemical Vapor Deposition (CVD) tec... more Networked films of carbon nanotubes (CNTs) have been grown by Chemical Vapor Deposition (CVD) technology onto cost-effective alumina substrate, coated by Cobalt nanocatalyst for growing the CNTs. The sidewalls of the CNTs films have been functionalized by spray-coating with two different metalloporphyrins (MPP), consisting of a Tetraphenylporphyrin coordinated by a central metal of zinc (Zn-TPP) and manganese (Mn-TPP). The surface-modification

Key Engineering Materials, 2004

In the present study, the resistance to surface abrasion of two commercial glazed ceramic tiles w... more In the present study, the resistance to surface abrasion of two commercial glazed ceramic tiles was determined according to the test method specified in the Standard ISO 10545-7 The worn areas of all the specimens were analysed using a non-destructive technique, an optical profilometer. These results, coupled with a morphological analyses carried out with a scanning electron microscope, allowed to understand the mechanisms acted during the material removal. Germany), equipped with a Vickers indenter at the following indentation loads 1. 95, 2.94, 4.90, 9.81 and 19.62N. At least ten valid impressions for each load were considered.

Advances in Science and Technology, 2006

Si-nanoparticles (NP) are attracting steadily growing interest due to their intriguing sizedepend... more Si-nanoparticles (NP) are attracting steadily growing interest due to their intriguing sizedependent optical properties. The most challenging task in preparing Si-NP is to succeed in controlling the particle size and size distribution and the surface properties. To this respect, the method of laser synthesis of Si-NP from gas phase reactants appears as an ideal tool, being a very versatile and controllable synthesis technique, but the collected Si-NP are strongly agglomerated.

Journal of Solid State Electrochemistry, 2011

This paper reports a study on the understanding of the performance decrease mechanisms of polymer... more This paper reports a study on the understanding of the performance decrease mechanisms of polymer electrolyte fuel cells under critical operating conditions. In order to investigate the durability of perfluorosulfonate membranes at low humidification conditions, long-term fuel cell tests have been carried out. Results evidenced a strong effect of low relative humidity on the commercial polymer membrane lifetime. Prolonged dehydration of the membranes led to a decrease of the three-dimensional reaction zone due to the ionomer degradation in the catalytic layer and a continuous loss of material in the membrane evidenced by a thickness decrease. The last effect provoked a collapse of the electrode structure.

Sensors and Actuators B-chemical, 2010

In this paper the effect of the surface functionalization of the carbon nanotubes (CNT) networked... more In this paper the effect of the surface functionalization of the carbon nanotubes (CNT) networked films with a metalloporphyrins layer is investigated for gas sensing. Modified film exhibits an increased sensitivity of the electrical resistance towards the concentrations of common volatile compounds (alcohols, amines, aromatic and ketones), at room temperature. Furthermore, a part of the adsorption properties of the functional units is transferred to the sensor signal and, as a consequence, the selectivity of the sensor is also modified. Principal Component Analysis (PCA) demonstrates that the functionalization provides enough selectivity change to turn a triplicate of the same CNT film into an effective sensor array capable of the compounds recognition.

Journal of Power Sources, 2008

An electrochemical method for the Pt nanoparticles deposition on porous and high surface carbon s... more An electrochemical method for the Pt nanoparticles deposition on porous and high surface carbon substrates (carbon black and carbon nanotubes), as an alternative way to prepare gas diffusion electrodes for polymer electrolyte fuel cells (PEFCs), is herein described. Pt nanoparticles well distributed and localized on the electrode surface were obtained by using an electric field. The electro-catalysts were prepared by single and multiple pulse galvanostatic polarizations in 1 M sulphuric acid + 5 mM exachloroplatinic acid solution. Chemical analysis, cyclic voltammetry and field emission gun scanning electron microscopy were used to determine the electrochemical features of Pt deposits and the influence of electro-deposition method on their nano-morphology. Electro-catalytic performances were studied by investigating the methanol oxidation reaction and the results are presented in form of surface specific activity and mass specific activity to take into account the electrochemical real surface and Pt loading. A comparison with commercial E-TEK Pt/C catalysts, prepared by traditional chemical reduction and heat treatment in hydrogen, shows that the electrodeposited catalyst presents higher activity at lower Pt loading.

Polymer Electrolyte Fuel Cells (PEFCs) offer low weight and high power density and are being cons... more Polymer Electrolyte Fuel Cells (PEFCs) offer low weight and high power density and are being considered for automotive and stationary power production besides space and electronic applications. In this work, gamma radiation effects on carbon materials (carbon powder and multiwalled carbon nanotubes) used as substrates in PEFCs electrodes, were studied. The enhancing of free radicals formation (especially on carbon powder) was observed and studied by EPR spectroscopy. This evidence leads to a significant activation of carbon materials because paramagnetic sites represent the preferential position for platinum electrocatalyst nucleation. Galvanostatic techniques were applied to deposits platinum nanoparticles on carbon substrates while FEG-SEM characterization and cyclic voltammetry (CV) were carried out to study the morphology and the electrochemical performances of PEFCs electrodes.

Networked carbon nanotubes (CNTs) films have been grown by chemical vapor deposition (CVD) techno... more Networked carbon nanotubes (CNTs) films have been grown by chemical vapor deposition (CVD) technology onto miniaturized Co-coated alumina substrates for NO2 and NH3 gas sensing applications, at a sensor temperature of 150°C. The sidewalls of the CNTs films have been modified by spray-coating with two different metalloporphyrins (MPPs) consisting of a TetraPhenylPorphyrin coordinated by a central metal of zinc (Zn-TPP) and manganese (Mn-TPP) for enhanced sensitivity and tailored specificity. It was demonstrated that the gas sensitivity of the MPPs-modified CNTs-sensors significantly improved by a factor up to four-times through a catalytic effect of the MPPs. The gas sensing properties of CNTs-sensors, including MPPs-modified CNTs, are characterized by a change of the electrical conductivity in a model of charge transfer with a semiconducting p-type character. A response of the CNTs-sensor functionalized with 2 spray-layers of Mn-TPP has been measured as 0.43% to 0.5 ppm NO2, and as 0.09% to 10 ppm NH3, at 150°C. The MPPs-functionalized CNTs-sensors exhibit high sensitivity, fast response, reversibility, good repeatability, sub-ppm range detection limit.

Advances in Science and Technology, 2006

Sensors and Actuators B-chemical, 2008

A gas chemiresistor, fabricated onto alumina using multi-walled carbon nanotubes (MWCNTs) network... more A gas chemiresistor, fabricated onto alumina using multi-walled carbon nanotubes (MWCNTs) networked films grown by radiofrequency plasma enhanced chemical vapor deposition (RF-PECVD) technology, is described for high-performance gas detection, at an operating temperature of 200 • C. Functionalizations of MWCNTs tangled bundle-films with nominally 5-nm thick Pt-and Pd-nanoclusters, prepared by magnetron sputtering, provide higher sensitivity for significantly enhanced gas detection of NO 2 , H 2 S, NH 3 , CO, up to a low limit of sub-ppm level. The measured electrical conductance of the functionalized MWC-NTs upon gas exposures is modulated by charge transfer with p-type semiconducting characteristics. Ptand Pd-nanoclusters functionalized MWCNTs gas sensors exhibited better performances compared to unfunctionalized MWCNTs, making them promising candidates for air-pollutants environmental monitoring. Simple electronic interface for the chemiresistor has been developed with a voltage output of the sensor signal.

Sensors and Actuators B-chemical, 2009

We investigate the impact of the tailored load of gold (Au) nanoclusters functionalizing the side... more We investigate the impact of the tailored load of gold (Au) nanoclusters functionalizing the sidewalls of the carbon nanotubes (CNTs) networks on gas sensing performance of a chemiresistor, operating at a working temperature in the range of 20-250 • C. CNTs networked films have been grown by radiofrequency plasma enhanced chemical vapour deposition (RF-PECVD) technology onto low-cost alumina substrate, provided with 6 nm nominally thick cobalt (Co) growth-catalyst. Nanoclusters of Au have been deposited by sputtering onto CNTs networks with a controlled loading of equivalent thickness of 2.5, 5 and 10 nm. Microstructure and morphology of the CNTs have been characterized by FE-SEM and TEM with diameter of the bundles of nanotubules of 10-40 nm. CNTs and Au-modified CNTs exhibit a p-type response with a decrease in electrical resistance upon exposure to oxidizing NO 2 gas and an increase in resistance upon exposure to reducing gases (NH 3 , CO, N 2 O, H 2 S, SO 2 ). Negligible response has been found for CNTs and Au-modified CNTs sensors exposed to CO, N 2 O, SO 2 . In the contrast, significantly enhanced gas response of NO 2 , H 2 S and NH 3 , up to a low limit of sub-ppm level, has been measured for Au-functionalized CNTs-chemiresistors. Highest gas sensitivity to NO 2 , H 2 S and NH 3 has been found by CNTs functionalized with Au loading of 5 nm, at 200 • C. An optimal operating temperature for each Au-modified CNTs-sensor exposed to NO 2 gas has been recorded. Good repeatability of the electrical response to 200 ppb NO 2 is also reported, at 200 • C. These results demonstrate the efficiency of the CNTs-chemiresistors functionalized with Au nanoclusters for selective air-pollutants environmental monitoring applications.

Procedia Chemistry, 2009

Networked films of carbon nanotubes (CNTs) have been grown by Chemical Vapor Deposition (CVD) tec... more Networked films of carbon nanotubes (CNTs) have been grown by Chemical Vapor Deposition (CVD) technology onto cost-effective alumina substrate, coated by Cobalt nanocatalyst for growing the CNTs. The sidewalls of the CNTs films have been functionalized by spray-coating with two different metalloporphyrins (MPP), consisting of a Tetraphenylporphyrin coordinated by a central metal of zinc (Zn-TPP) and manganese (Mn-TPP). The surface-modification