Palladium–polyelectrolyte hybrid nanoparticles for hydrogen sensor in fuel cells (original) (raw)
Related papers
Polystyrene Palladium Nanocomposite for Hydrogen Sensing
Molecular Crystals and Liquid Crystals, 2005
In this paper, we report on the structure and hydrogen gas sensing properties of polystyrene palladium nanowire composites. Granular palladium nanowires (with 250 nm diameter) have been electrodeposited on Highly Oriented Pyrolytic Graphite (HOPG). In order to measure the electrical response of the sensor the nanowires were transferred to an insulating polystyrene surface. Polystyrene thin films with the thickness of about 150 nm were formed on a glass microslide by a dip-coating technique from a chloroform solution. Silver microelectrode pads were patterned on the surface of the nanocomposite by shadow masking technique. All stages of sensor device fabrication and its mechanism were monitored with application of atomic force microscopy technique (contact, non-contact, and force modulation modes).
Shape dependent hydrogen response in palladium nanoparticle based sensors
Materials Today: Proceedings, 2020
Palladium nanoparticles (Pd NPs) with well-defined shape and controllable size were synthesized by Polyol strategy and the shape effect on hydrogen sensing at room temperature (RT) and beyond RT was detected. The evolution of shape in Pd NPs was dependent on the amount of stabilizer [Polyvinylpyrrolidone (PVP)] used during synthesis. Further, the dominant morphological facet in a particular shape determined whether the material will be suitable for room temperature or high temperature applications. The particle shape and facet hierarchy were analyzed using High Resolution Transmission Electron Microscopy (HRTEM) images, and Selected Area Electron Diffraction (SAED) patterns respectively. The hydrogen sensor studies revealed good response characteristics and the response parameters varied with the change in shape/facet characteristics of Pd nanoparticles. Also the variation of the hydrogen response with the increase in operating temperature was different for different shapes.
Role of Capping Agent in Palladium Nanoparticle Based Hydrogen Sensor
Journal of Cluster Science, 2018
Palladium (Pd) nanoparticles (NPs) were synthesized via polyol route by varying concentration of capping agent, polyvinylepyrollidone (PVP). High resolution TEM study showed that the palladium nanoparticles were nearly spherical shape in the size range 11-13 nm. Hydrogen response pattern of the devices fabricated with the synthesized Pd NPs were recorded and were found to vary with the concentration of PVP. Also, response magnitude increased with PVP concentration for a particular pattern. Smooth recovery was observed both with and without the flow of carrier gas. While the sensor performance was found to be best at room temperature, the device performance deteriorated with the increase in temperature. Excellent long-term stability was observed as the devices showed similar response after 30 days of testing. The reproducible hydrogen response of these devices was supported by X-ray diffraction studies done on samples before and after hydrogen sensor study. The variation in response with the concentration of PVP is corroborated with a suitable sensing mechanism.
Palladium-Functionalized Nanostructured Platforms for Enhanced Hydrogen Sensing
Nanomaterials and Nanotechnology, 2016
This paper reports on miniaturized hydrogen sensing platforms, exploring several means of fabricating nanostructured films and evaluating their sensing characteristics. Palladium-sputtered nanoporous organosilicate matrices are fabricated using the polymeric system [polymethylsilsesquioxane (PMSSQ); polypropylene glycol (PPG); propylene glycol methyl ether acetate (PGMEA)] followed by volatilization of the liquid phase, i.e., PGMEA and PPG at their boiling points. In order to provide greater adsorption/desorption sites for the test gas, ultra-dense ZnO nano-brushes with very high aspect ratios are successfully fabricated in the porous template. Thereafter, functionalization of ZnO is performed by sputter coating thin Pd films onto the ZnO surface. Intensive characterization for these nanostructures is performed using FESEM, EDAX, FTIR, TEM and AFM techniques. Comparison of all fabricated sensing platforms for hydrogen gas-dependent responses based on temperature, as well as test gas concentrations at various ppm levels, is performed. Palladium coating of ZnO nano-brushes renders this film highly selective to hydrogen and also improves its sensitivity by a factor of ~66% relative to the uncoated film. Sensitivity to hydrogen is found to be ~70% and a selectivity test is performed with CO 2 and CH 4, with sensitivities of 5% and 7%, respectively. Pd-functionalized ZnO nano-brushes display enhanced hydrogen response behaviour.
Journal of Physics D: Applied Physics, 2011
This study reports a promising, cost-effective nanoscale hydrogen sensor fabricated using the dielectrophoresis (DEP) process. Palladium nanoparticles (NPs) of diameter in the range 2-4 nm were assembled in a 20 nm gap between electrodes under optimized DEP parameters of frequency, voltage and assembling time of 1 M Hz, 1.5 V and 90 s, respectively. The fabricated nanoscale device was powered by applying a dc voltage of 10 mV across nanogap electrodes and temporal change in resistance at an operating temperature of 160 • C was recorded in the presence of 3000 ppm of hydrogen gas. A rise and recovery times of 100 s and 300 s, respectively, in the temporal hydrogen gas response characteristic were observed which could be attributed to the hydride formation due to the strong affinity of assembled palladium NPs towards hydrogen. The nanoscale device was sensitive enough to respond to hydrogen presence even at 30 • C. Preliminary results show the potential of DEP in fabricating cost-effective nanoscale hydrogen sensor.
Sensors and Actuators B: Chemical, 2009
A novel amperometric sensor for hydrogen peroxide (H 2 O 2 ) was developed based on palladium nanoparticles (NPs) in-situ formed on the electrode surface. Poly(acrylic acid) (PAA) was first electrodeposited onto a gold electrode. Then Pd 2+ were chemically adsorbed within the PAA network, and subsequently reduced by hydrazine hydrate to form palladium NPs. The size and density of palladium NPs can be easily controlled through controlling the amount of metal ions in the film. The PAA-templated Pd NPs displayed excellent electrocatalytical response to the reduction of H 2 O 2 . Under optimal conditions, linear relationship was observed for H 2 O 2 reduction in the concentration range from 10 M to 25 mM at the applied potential of −0.1 V and the detection limit was 5 M. The resulted sensor shows fast response and good stability. By varying the metal catalyst and by conjugating biomolecules with the free carboxyl groups of PAA, a variety of new chemical and biosensors could be constructed.
Polymer-Nanoparticle Hybrid Materials for Plasmonic Hydrogen Detection
2021
Plasmonic metal nanoparticles and polymer materials have independently undergone rapid development during the last two decades. More recently, it has been realized that combining these two systems in a hybrid or nanocomposite material comprised of plasmonically active metal nanoparticles dispersed in a polymer matrix leads to systems that exhibit fascinating properties, and some first attempts had been made to exploit them for optical spectroscopy, solar cells or even pure art. In my thesis, I have applied this concept to tackle the urgent problem of hydrogen safety by developing Pd nanoparticle-based "plasmonic plastic" hybrid materials, and by using them as the active element in optical hydrogen sensors. This is motivated by the fact that hydrogen gas, which constitutes a clean and sustainable energy vector, poses a risk for severe accidents due to its high flammability when mixed with air. Therefore, hydrogen leak detection systems are compulsory in the imminent large-scale dissemination of hydrogen energy technologies. To date, however, there a several unresolved challenges in terms of hydrogen sensor performance, whereof too slow sensor response/recovery times and insufficient resistance towards deactivation by poisoning species are two of the most severe ones. In this thesis, I have therefore applied the plasmonic plastic hybrid material concept to tackle these challenges. In summary, I have (i) developed hysteresis-free plasmonic hydrogen sensors based on PdAu, PdCu and PdAuCu alloy nanoparticles; (ii) demonstrated ultrafast sensor response and stable sensor operation in chemically challenging environments using polymer coatings; (iii) introduced bulk-processed and 3D printed plasmonic plastic hydrogen sensors with fast response and high resistance against poisoning and deactivation.
Journal of Electronic Materials, 2020
The size attributes in palladium nanoparticle yield were found to influence the hydrogen sensor response in resistive devices, and the sensing mechanism was correlated with the variation of particle size from large to small in a particular synthesis product. The quantity of polyvinylpyrrolidone (PVP), the stabilizer used in this study, was varied during synthesis, and the resulting sizes were determined by high-resolution transmission electron microscopy (HRTEM). The size tuning by the capping agent PVP was also confirmed by UV-Vis spectroscopy via a detailed analysis of the experimental spectra, which revealed an interesting shift of the major absorption peaks with the increase in PVP. Glancing-angle x-ray diffraction (GAXRD) studies were undertaken to highlight the face-centred cubic crystallinity of the drop-cast nanofilms on thin glass substrates, as well as to evaluate the variation in crystallite cluster size by analyzing the major diffraction peaks. The size variation from HRTEM and GAXRD studies was found to match within the limits of experimental accuracy. The hydrogen sensor studies showed good room temperature response with typical size-dependent characteristics. The mechanistic control of the hydrogen activity over the mixed sized nano-films at room temperature (RT) and beyond RT is elaborately discussed.
Ciência e Natura, 2015
Palladium nanostructures have been deposited onto the stainless steel electrode by simple electrochemical deposition method in a buffer solution. The morphology of the synthesized Pd nanoparticles is controllable by deposition potentials because the driving force for various crystal growth mechanisms is merely dependent on applied potentials. The deposited Pd nanoparticles at higher applied potentials showed a cauliflower-like morphology with a nanoscale structure and large surface area. Then, an amperometric hydrogen sensor based on Pd nanoparticles can be constructed. This sensor is based on polymer electrolyte membrane fuel cell (PEMFC) and can be used at the ambient temperature. It is operated in the three-electrode mode that consists of three electrodes (working, counter and reference) and protonated Nafion membrane as proton conducting solid polymer electrolyte (SPE). The steady-state current response is obtained linearly to the concentrations of hydrogen from 50 to 2000 ppm, ...