Palladium Metal Research Articles

Reaction of Highly Dispersed Nickel Metal Powders with Pd(II) Aqueous Solutions under Hydrothermal Conditions

The processes of contact reaction of nickel metal powders with aggregated particle sizes of 300–400 nm with aqueous solutions of palladium(II) in autoclaves at elevated temperatures in acidic and alkaline media have been studied. It has been found that when metallic nickel contacts with aqueous solutions of palladium(II) chloride in 0.01 M hydrochloric acid at temperatures of 100 and 130°C for 15 min, the concentration of divalent palladium ions decreases to zero. The process is accompanied by a partial transition of nickel into solution. The precipitates are a mixture of metallic particles of nickel and palladium of variable compositions. In the case of contact of metallic nickel with solutions of tetraammine palladium(II) chloride at temperatures of 160 and 170°C in a medium of 0.1 M potassium hydroxide, metal palladium particles 5–25 nm in size are formed on the surface of larger nickel particles. The structure of bimetallic particles has been determined by X-ray photoelectron microscopy.

Construction of Marigold-like Poly(vinyl alcohol) Microspheres for Catalytic Microreactors.

It has long been pursued to develop polymer microspheres with various special morphologies and structures for better results in applications such as catalysis, drug delivery, and bioscaffolds. However, it remains a challenge to develop a facile method to produce poly(vinyl alcohol) (PVA) microspheres with special morphologies. Herein, a micron-sized marigold-like poly(vinyl alcohol) (CE-PVATPA) microsphere was engineered and fabricated by a feasible strategy, that is, emulsification-cross-linking, freeze-drying, and secondary acetal reaction steps. The morphological evolution of microspheres was systematically investigated under different conditions, and the procedure of constructing PVA microspheres with stabilizing marigold-like structures was proposed. More importantly, a specially structured PVA microsphere microreactor synergistically loading palladium metal nanoparticles (CE-PVATPA@Pd) for the heterogeneous catalyst 4-nitrophenol (4-NP) could be further demonstrated, which indicated high catalytic activity and excellent recyclability. The resultant stabilized fabricating method is promising to provide valuable guidance for the design and fabrication of a high-performance PVA microsphere microreactor.

A stereoselective nontraditional Heck reaction mechanism: Origins of enantioselectivity and diastereoselectivity

Nontraditional Heck-type reactions of C = heteroatomic variants have been a great challenge. Herein, we computationally investigate a nontraditional stereoselective Heck mechanism regarding hydrazone C = N-NH2 by using density functional theory (DFT) methods. Calculations indicate that the total potential barrier of the conversion is 25.6 kcal/mol, which is reasonable to be crossed under the current reaction conditions. Unlike C = C π-bonds, the coordination of C = N with transition metal palladium into a η1-complex is confirmed. A larger π-bond insertion barrier for C = N is required, which is rationalized by frontier molecular orbital (FMO) analysis with a wider LUMO-HOMO energy gap. π-bond insertion is the enantioselectivity determining step of the strategy and that the pathway toward the R-isomer exhibits a much lower energy barrier (24.2 vs 40.1 kcal/mol). π-bond insertion is also the diastereoselective control step with using DBBP ligands. Non-covalent interaction (NCI) analysis confirms that greater spatial hindrance is responsible for the stereoselectivity of the protocol. Meanwhile, calculations show that using an acid-promoted tactic can effectively improve the in situ production of hydrazone and significantly reduce the energy barrier.

A novel deep-learning technique for forecasting oil price volatility using historical prices of five precious metals in context of green financing – A comparison of deep learning, machine learning, and statistical models

This study proposes a novel deep-learning convolution neural network (CNN) to forecast crude oil prices based on historical prices of five precious metals (Gold, Silver, Platinum, Palladium, and Rhodium) in context of green financing. The proposed deep learning CNN has three components: a convolution block called a group block, a novel convolutional neural network architecture called GroupNet, and a regression layer. The proposed model is tested against seven machine learning models and three traditional statistical models for predicting oil price volatility using the same independent variables (5 precious metals). A comparison of the deep learning model (our proposed model) with machine learning/deep learning models and statistical methods indicates that the proposed deep learning model has the highest prediction accuracy. A feature selection technique is also applied using the WEKA ML tool to improve the accuracy of the proposed model and existing machine learning and traditional statistical models. The findings indicate a non-linear correlation between oil price volatility and prices of precious metals. Moreover, statistical analysis indicates that deep learning can be used to predict oil price volatility with greater accuracy than machine learning and statistical methods while using precious metals as predictors. The results also indicate that machine learning models (Decision Tables and M5rules) can be used to predict oil price volatility with considerable accuracy. Moreover, the study proves that traditional statistical models can perform better than a few machine learning models (Lazy LWL and GPR).

Applying Heterogeneous Catalytic Reactions for Organic Chemical Syntheses

In this review the most important results achieved in the recent 12–15 years are summarized focusing on the heterogenous catalytic hydrogenations over transition metals (Pd, Pt, Ru, Rh, La), as well as the application of palladium, copper and other metals on a molecular sieve (4A) support in several organic chemical syntheses in liquid phase.

Physicochemical characterization and anticancer activity of the new imipramine based Co(II), Pd(II) and Mn(II) compounds

Three new imipramine-based compounds, namely: (HIMP)2CoCl4, (HIMP)2Pd2Cl6 and (HIMP)2MnCl4 (HIMP = protonated imipramine) were synthesized in a single-step reaction between imipramine hydrochloride and metal(II) chlorides. The physicochemical properties of all three compounds were thoroughly investigated using appropriate analytical techniques: single crystal and powder X-Ray diffraction analysis, elemental analysis, UV–Vis and FTIR spectroscopies, fluorescence measurements, quantum mechanical calculations, TG-DTG thermogravimetric analysis and magnetic studies. The investigations proved the high purity of the compounds and the isostructurality of (HIMP)2CoCl4 and (HIMP)2MnCl4 compounds. Of all compounds, only (HIMP)2MnCl4 exhibited fluorescent properties. When heated, all three compounds decompose, yielding the appropriate metal(II) oxides in the case of (HIMP)2CoCl4 and (HIMP)2MnCl4 compounds or metallic palladium in the case of (HIMP)2Pd2Cl6. In the last step, the anticancer activity of all three compounds was evaluated against MKN-74, PANC-1, SCOV-3, MDA-MB-231, MDA-MB-468, A-375 and SK-MEL-28 cell lines. Cytotoxicity evaluation revealed that the incorporation of the active metal ions significantly increased the imipramine activity against all tested cancer cell lines without significant toxicity against normal fibroblasts.

Recent Progress in Palladium Catalysed Sustainable Synthesis of Heterocycles

Background: Palladium metal has been extensively used in the synthesis of organic molecules for the last few decades. Heterocyclic ring synthesis being a significant part of organic synthesis, transition metal catalysis, especially catalysis by palladium, has been actively employed in heterocyclic synthesis. However, since palladium is an expensive metal, there has always been an urge to reuse or recycle the palladium catalyst to make the process economically viable. Modern synthetic chemists are also in constant search for newer sustainable strategies for molecular synthesis, which will lead to eco-friendly synthetic protocols. Thus, in the last few years, palladium catalysed green synthesis of heterocycles has gained importance as these aim to make the synthetic organic chemical world slightly more sustainable. Methods: This review comprises palladium catalysed synthetic strategies that proceed in a sustainable fashion. A few protocols included here involve either organic solvent-free or greener solvents as reaction medium, which is one of the modes adopted towards sustainability. Other modes of sustainability included in this review are recyclability of the palladium catalyst, one pot tandem reaction strategy, use of air as oxidant, etc. All these modes aim at achieving one or the other green chemistry principles like reduction of waste and by-products, increasing atom economy, reduction of cost and use of safer solvents. Results: The review aims to reflect the scope of sustainability in palladium catalysed synthesis of heterocycles so that economically and environmentally viable synthetic methodologies may be selectively identified and applied in academia and industries. Conclusion: Keeping the principles of green chemistry in mind, in this review, we aim to compile the recent advancements in palladium catalysed sustainable synthesis of heterocycles in a single platter that may serve as a piece of reliable literature for further research in this area.

Mapping Atomic-Scale Metal-Molecule Interactions: Salient Feature Extraction through Autoencoding of Vibrational Spectroscopy Data.

Atomic-scale features, such as step edges and adatoms, play key roles in metal-molecule interactions and are critically important in heterogeneous catalysis, molecular electronics, and sensing applications. However, the small size and often transient nature of atomic-scale structures make studying such interactions challenging. Here, by combining single-molecule surface-enhanced Raman spectroscopy with machine learning, spectra are extracted of perturbed molecules, revealing the formation dynamics of adatoms in gold and palladium metal surfaces. This provides unique insight into atomic-scale processes, allowing us to resolve where such metallic protrusions form and how they interact with nearby molecules. Our technique paves the way to tailor metal-molecule interactions on an atomic level and assists in rational heterogeneous catalyst design.

Soft X-ray Fermi surface tomography of palladium and rhodium via momentum microscopy

Fermi surfaces of transition metals, which describe all thermodynamical and transport quantities of solids, often fail to be modeled by one-electron mean-field theory due to strong correlations among the valence electrons. In addition, relativistic spin–orbit coupling pronounced in heavier elements lifts the degeneracy of the energy bands and further modifies the Fermi surface. Palladium and rhodium, two 4d metals attributed to show significant spin–orbit coupling and electron correlations, are ideal for a systematic and fundamental study of the two fundamental physical phenomena and their interplay in the electronic structure. In this study, we explored the Fermi surface of the 4d noble metals palladium and rhodium obtained via high-resolution constant initial state momentum microscopy. The complete 3D-Fermi surfaces of palladium and rhodium were tomographically mapped using soft X-ray photon energies from 34 eV up to 660 eV. To fully capture the orbital angular momentum of states across the Fermi surface, the Fermi surface tomography was performed using p- and s- polarized light. Applicability and limitations of the nearly-free electron final state model in photoemission are discussed using a complex band structure model supported by experimental evidence. The significance of spin–orbit coupling and electron correlations across the Fermi surfaces will be discussed within the context of the photoemission results. State-of-the-art fully relativistic Korringa–Kohn–Rostoker (KKR) calculations within the one-step model of photoemission are used to support the experimental results.

Highly efficient and selective adsorption of palladium(II) from simulated nuclear waste solution using Amberlite XAD-7 resin impregnated with a phenanthroline-derived diamide

The increasing demand and limited natural resources for rare precious metal palladium render its separation and recovery from secondary sources such as acidic nuclear liquid waste greatly interesting. Herein, a novel Et-Tol-DAPhen extraction resin was prepared by impregnating Amberlite XAD-7 resin with a phenanthroline-derived diamide extractant N,N′-diethyl-N,N′-ditolyl-2,9-diamide-1,10-phenanthroline (Et-Tol-DAPhen), and the adsorption behavior of this new extraction resin towards Pd2+ in HNO3 solution was investigated through the batch and column experiments. The Et-Tol-DAPhen extraction resin exhibited strong adsorbability, high adsorption capacity, excellent selectivity and good reusability for Pd2+ in highly acidic HNO3 solution. In addition, the pseudo-second-order and Langmuir models were applied to understand the adsorption process of Pd2+ on Et-Tol-DAPhen extraction resin, respectively. It demonstrated the characteristics of a uniform single-layer chemisorption. The maximum uptake capacity could reach as high as 74.6 mg g−1 for Pd2+ in 3.0 mol/L HNO3 solution which is much higher than most adsorbent materials of palladium reported before. Furthermore, Et-Tol-DAPhen extraction resin could selectively uptake Pd2+ from a simulated acidic nuclear waste solution containing 20 different kinds of ions with the separation factor SFPd/M values as high as 100 to 10,000. Moreover, although the adsorption efficiency had a slight decrease after 5 times of adsorption-desorption process, it still remained at a high level. This new extraction resin displayed a potential application prospect in the field of separation and recovery of Pd2+ from acidic nuclear liquid waste.

Interactive effects of palladium (Pd) and microplastics (MPs) on metal bioaccumulation and biological responses in the Mediterranean mussel, Mytilus galloprovincialis

This study investigates the potential of MPs as carriers of pollutants as they can strengthen bioaccumulation of toxic metals on marine organisms. For the first time, the interaction of the metal palladium (Pd) with the widespread MPs, both with increasing concentrations in water environments from anthropogenic sources, was tested. Mytilus galloprovincialis, an important seafood product, was exposed to Pd (24 h) in two ways: water-dissolved and MPs-adsorbed, with depuration followed for 144 h. Quantification of Pd in tissues shown an accumulation 2–3 times higher (59 % of initial Pd) for mussels exposed to MPs-adsorbed Pd and higher in digestive gland than when exposed to water-dissolved Pd (25 %; higher in gills). Additionally, it was demonstrated that Pd induced oxidative stress and altered the feeding behavior of mussels. Therefore, this work support MPs as being vectors of metals (i.e. Pd) to enhance their bioaccumulation on marine organisms which highlights ecological risk of these emerging pollutants.

Anchoring Pd nanoparticles on metal–organic frameworks for SO2 detection

Enhancing the electron transport capability of metal–organic framework (MOF) materials, which are novel gas sensing materials, remains a formidable challenge. In this study, palladium metal nanoparticles (Pd-NPs) were successfully anchored on the surface of ZIF-8, a porous material, by using chemical reduction to improve the gas sensing performance of ZIF-8 significantly. The active catalytic sites of Pd-NPs are stimulated by the porous structure of ZIF-8 and are uniformly dispersed on the surface of the porous ZIF-8 material. The Pd-NPs/ZIF-8 composite material has good response and selectivity for up to 200 ppm SO2 at 300 °C (gas sensing response of 86.61%), a fast response time (approximately 24 s), low detection limit (4.0 ppb) and excellent stability and anti-interference ability. These outcomes can be attributed to the fact that anchoring Pd-NPs on the surface of the porous ZIF-8 material can effectively improve gas sensing performance by exploiting the high conductivity and catalytic activity of Pd-NPs through electron and chemical sensitisation.

Defect engineering on metal oxides (Zn, Mo and Fe) and their impact on the crude glycerol biofuel oxidation

Defect engineering is an interesting area to improve the activity for alcohols oxidation because it promotes electronic changes through induced defects like oxygen vacancies (Ov) or doping with heteroatoms. Herein, Pd/Ov‒induced metal oxides bimetallic nanomaterials (Pd/Ov‒Fe2O3, Pd/Ov‒ZnO and Pd/Ov‒MoO3) were successfully synthesized and defect‒engineered boosting oxygen vacancies in the order ∼9–15%. The resulting materials had similar crystallite sizes (∼7.1 nm), metal‒support compositions (∼20 wt %), and bimetallic compositions (metal oxide ∼20 wt %). Electrochemical tests demonstrated that despite ZnO presented improved Ov, the electronic interaction between Pd and Ov‒Fe2O3 allowed to obtain higher current density (jmax). Pd/Ov‒Fe2O3 presented a jmax of 197.66 mA mg−1, being up to 2.2 times higher to that of Pd/C, while Pd/Ov‒MoO3 presented the most negative onset potential (−0.30 V). Electrochemical impedance spectroscopy, apparent activation energy tests and cyclic voltammetry tests involving synthetic solutions of glycerol, methanol and glyceraldehyde confirmed that the decrease of the onset potential is related to an enhanced electron transfer by Pd/Ov‒MoO3 resulting also in a decrease of the apparent activation energy (11.22 kJ mol−1). While the improved jmax of Pd/Ov‒Fe2O3 was related to its capability to oxidize crude glycerol and the mixtures because the efficient interaction between the defected metal oxide and palladium.

Environmental and Social Life Cycle Assessment of Waste Electrical and Electronic Equipment Management in Italy According to EU Directives

The current Waste Electrical and Electronic Equipment (WEEE) management system of the European Union to be applied in all member states was introduced in 2002 by the first WEEE directive (2002/96/EC). Since the beginning, the system was intended to improve the management of WEEE and promote circular economy principles in the sector. This study aims at evaluating the environmental and social impacts of the WEEE management system in Italy, with a special focus on collection and recycling in Campania Region (the third more populated Italian Region, Southern Italy). The Life Cycle Assessment (LCA) is jointly applied with the Social Life Cycle Assessment (S-LCA). All five categories of WEEE (R1 to R5) are considered in the assessment. The LCA results show that the extraction of metals and materials from 1 tonne of WEEE collection and recycling generates much lower environmental impacts than the extraction and refining of an equivalent amount of virgin resources. In particular, the results of the environmental LCA highlight that the treatment of 1 tonne of WEEE collected in the Campania Region provides the opportunity to recover several metals such as Aluminum, Iron, Steel and ferrous materials, Copper, Nickel, Lead, and precious metals (Gold, Silver, and Palladium). According to S-LCA, the collection and recycling of 1 tonne of WEEE provides positive impacts to the investigated sub-categories of recipients (i.e., local community and society), except in some cases where the collection may potentially generate negative impacts, expressed by a lower “safe and healthy living conditions” indicator in the local community sub-category. In particular, much more must be done to support small Municipalities towards better collection procedures and integration within the largest Regional and national WEEE valorization networks. Solutions are suggested to improve the transition of the WEEE management system towards a more just environmental and social circular economy model.

Recovery of Metal Ions from Aqueous Solutions by γ-Alumina Creates Value-Added Catalyst Products

Mining and extracting metals from hard rock adversely impact the environment. These impacts could be mitigated by capturing dissolved metals from water (i.e., mine runoff, industrial wastewaters, or even tap water) and converting the metals to products with potential economic benefits (i.e., upcycled into high-value products). We sought to identify a sorbent that can remove dissolved metals from water and in the process of this low-temperature surface adsorption create a catalytic material of potential economic value. We discovered that γ-aluminum oxide (γ-Al2O3) can produce a reactive catalyst after removing metal ions (copper (Cu), palladium (Pd), nickel (Ni), and cobalt (Co)) from water, even for dissolved metals at environmentally relevant concentrations. The resulting metal-coated γ-Al2O3 behaved, comparable to high-temperature produced catalysts, as a mono- or bimetallic catalyst capable of oxidizing or reducing pollutants (methylene blue, 4-nitrophenol, nitrite, and nitrate). Mono- or bimetallic catalysts synthesized from tap water with metal ions present efficiently oxidized methylene blue (by Cu/γ-Al2O3) or reduced nitrate (by Pd–Cu/γ-Al2O3) into less harmful species (i.e., ammonium and dinitrogen gas). Results demonstrated the versatile use of γ-Al2O3 that removes metal ions from water (i.e., water purification) and produces a valuable γ-Al2O3-based byproduct with proven catalytic reactivity (i.e., catalyst production) and commercial markets.

Mesomorphism and luminescence in coordination compounds and ionic salts based on pyridine-functionalized β-diketones. Influence of the pyridine nitrogen position

Pyridine-functionalized β-diketones with the pyridine nitrogen atom at 3 or 4 position (L3N and L4N, respectively) have been used as building blocks to obtain two new families of compounds with mesomorphic and luminescent behaviors. The N-pyridine coordination of the β-diketones to zinc(II), palladium(II) and platinum(II) metal centers has allowed to synthesize neutral coordination compounds of the type [MCl2(LZN)2] (M = Zn(II), Pd(II), Pt(II); Z = 3, 4). Particularly, coordination of L4N towards Pt(II) gives rise to the cationic species [Pt(NH3)2(L4N)2]2+. Otherwise, protonation of the pyridine moiety was strategically used to obtain a novel series of pyridinium ionic salts of the type (HLZN)nA (n = 1, A = Cl; n = 2, A = MCl4, M = Zn(II), Pd(II), Pt(II); Z = 3, 4). The neutral or ionic nature of the complexes, as well as the β-diketone ligands and the metal center in both the neutral and anionic complexes, has a great influence on the mesomorphic behavior. Thus, columnar or smectic mesophases can be selectively formed. Single-crystal and temperature-dependent powder X-ray diffraction studies have been performed to analyze the molecular packing in the crystal and the supramolecular ordering in the mesophase. All the aforementioned factors also play a key role on the luminescence properties, the Zn(II) coordination compounds and ionic salts being the best candidates as bifunctional materials.

A novel combination of graphene oxide/palladium integrated polycaprolactone nanocomposite for biomedical applications

To design a multi-biofunctional polymeric nanocomposite for therapeutic applications, biocompatible graphene oxide-palladium (GO-Pd) nanostructures were incorporated into a polycaprolactone (PCL) system. Metallic palladium nanoparticles were anchored over the graphene system through simple electrostatic interaction without reducing graphene oxide (GO). The XPS, XRD, SEM, TEM, EDAX, FTIR, and Raman spectral analysis divulged that the nanohybrid system consists of graphene layers embedded with spherically shaped palladium nanoparticles (PdNPs). Additionally, the optical characteristics of the hybrid system illustrate the surface plasmon resonance offered by metallic PdNPs on graphene. The hemocompatibility test corroborates the compatibility of nanostructures with biological systems. Multifunctional polymeric nanocomposites were obtained by integrating the GO-Pd nanoparticulate system into the PCL matrix. The PCL-GO-Pd nanocomposite was identified to be biodegradable and mechanically stable with enhanced surface wettability. Additionally, PCL-GO-Pd nanocomposite demonstrated distinguished bactericidal activity towards both S. aureus and E. coli due to the synergistic effect of GO and PdNPs, via oxidative stress and cell membrane disruption. Moreover, the hybrid nanocomposite showed remarkable antibacterial efficacy, biomineralization, and cell viability, affirming its bioactive behavior. Therefore, the current research introduces a biocompatible polymeric nanocomposite with considerable biological performance for various therapeutic applications, particularly for bone tissue regeneration.

Electrochemical Reduction of Pd-Nd2O3-CeO2 Mixtures in the LiCl-Li2O Melt

The electrochemical reduction of pelleted heterophase powder Pd-Nd2O3-CeO2 mixtures was studied in molten LiCl-Li2O (1–1.5 wt%) at 650 °C. The influence of the composition of the mixture, as well as electrochemical factors—i.e., the amount of electricity passed and the cathode potential during electrolysis—were considered. It was found that in the presence of metallic palladium, neodymium and cerium oxides are reduced by lithium released at the cathode and form intermetallic compounds of different compositions. At potentials more positive than the formation of a phase based on liquid lithium at 0.5–0.8 V, CePd3 and NdPd3 intermetallic compounds are present in the reduced product. At potentials close to the formation of liquid lithium, a whole spectrum of intermetallic compounds is synthesized: CePd, NdPd, Ce3Pd4, and Nd3Pd4. The mechanisms of formation of palladium alloys with neodymium and cerium are proposed and considered. The degree of the reduction of lanthanide oxides was calculated from the data on the concentration of residual oxygen in the reduced product.

Mixed reaction gold as versatile plating solution for ENIG, ENEPIG and EPAG plating

The surface finish on a printed circuit board (PCB) or substrate serves as surface protection and at the same time enables a variety of assembly techniques. Depending on which final finish is selected it allows for e.g. soldering connections or wire bonding by Al, Au or even Cu-wires. Surface finishes are typically characterized by different metal layers, including tin, nickel, palladium or gold. In this context the electroless or immersion plating of gold has a long history in the electronics industry. The gold plating represents a key step in different finish systems such as electroless nickel/immersion gold (ENIG), electroless nickel/electroless palladium/immersion gold (ENEPIG) and electroless palladium/autocatalytic gold (EPAG). ENIG, ENEPIG and EPAG finishes are characterized by their capabilities to be used as solderable and wire-bondable finish with specific benefits for ENEPIG and EPAG such as enhanced solder joint reliability and gold-wire bondability. In this paper an overview is given on the different types of electroless gold plating electrolytes from fully immersion type and autocatalytic type to mixed reaction type gold electrolytes. The details of the various plating mechanisms are presented, and the different properties and capabilities of these electrolytes are compared and explained based on the respective mechanisms. The presented study investigates the performance of a gold electrolyte of a mixed reaction type looking into the layer properties as well as the soldering and bonding capabilities. The results show that a mixed reaction gold electrolyte can be capable for versatile application- ENIG, ENEPIG and EPAG. The capability of the process was tested with respect to the solder wetting performance, solder joint reliability, wire bonding performance, corrosive attack to the nickel and thickness distribution. It can be shown that this gold process passes or exceeds all related industry standards and target requirements for ENIG, ENEPIG and EPAG final finishes.

Performance Investigation of Dual Trench Split-Control-Gate MOSFET as Hydrogen Gas Sensor: A Catalytic Metal Gate Approach

In this article, Dual Trench Split-Control-Gate MOSFET (DT-SCG-MOSFET) based hydrogen gas sensor considering catalytic palladium metal gate approach is simulated using SILVACO ATLAS TCAD. The inner gate architecture in addition to the outer control gates provides enhanced carrier control. Shift in surface potential, subthreshold current, linear current and threshold voltage are used to investigate the performance of the proposed gas sensor. The contribution of analog metrices like the transconductance and parasitic capacitances are explored thoroughly. Sensitivity as a function of subthreshold current as well as change in threshold voltage for the presence and absence of hydrogen gas molecules have been discussed. Results exhibit the superiority of the proposed gas sensor compared with the reported models in terms of sensitivity and Ion/Ioff ratio and suitable for hydrogen gas detection.