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Slow kinetics and emotive design of electrocatalysts are the main barriers to effective oxygen evolution and hydrogen production from water. To overcome these challenges, nickel sulfide impregnated electrocatalysts with auxiliary structural features have recently attracted attention as effective alternatives for the oxygen evolution reaction (OER). Herein, nickel sulfide (NiS) nanowires are developed directly on nickel foam (NF), which have proven to be a highly efficient electrocatalyst for OER in an alkaline medium. For this, NiS nanowires were grown on NF for short intervals of 30, 60, 90 and 120 min through an aerosol-assisted chemical vapor deposition (AACVD) process using nickel diethyldithiocarbamate as a precursor. The as-developed NiS electrode showed excellent OER activity in 1.0 M KOH solution. It is noteworthy that the NiS electrode produced after 90 min provides a reference current density of 10 mA cm−2 at an overpotential (η) of 210 mV and achieves a higher current density of 500 mA cm−2 at an overpotential of 340 mV. Moreover, the nanocatalyst has observed a low Tafel value (60 mV dec−1) and good OER stability. After the electrolysis, it was found that the surface of the NiS catalyst was partially modified into nickel oxide. The S atom in the NiS catalyst can provide an activator function that first converts the sulfide to a hydroxide and then eventually becomes an oxyhydroxide species. The more active nickel hydroxide/oxyhydroxide phase raises the water oxidation performance to a new level. The facile synthesis of NiS nanowire films by AACVD tends to be used as an anodic material in various other power generation and energy conversion devices such as batteries, fuel cells, and supercapacitors.

The phase formation behavior of β′-SiAlON with the general formula Si6-zAlzOzN8-z was studied comprehensively for z values from 1 to 3 using spark plasma sintering (SPS) as the consolidation technique at synthesis temperatures from 1400 to 1700 °C. The samples were prepared close to the β′-SiAlON composition line: Si3N4 − 4/3(AlN·Al2O3) in the phase diagram using (A) nano-sized amorphous Si3N4 and (B) micro-sized β-Si3N4 precursors. Field-emission scanning electron microscopy (FESEM) was used for microstructural analysis. Most compositions reached almost full density at all SPS temperatures. Compared with the micro-sized β-Si3N4 precursor, the nano-sized amorphous Si3N4 precursor accelerated the reaction kinetics, promoting the formation of dense β′-SiAlON + O′-SiAlON composites after SPS at synthesis temperatures of 1400–1500 °C. This resulted in very high values of Vickers hardness (Hv10) = 18.2–19.2 GPa for the z = 1 composition related to the hardness of the O′-SiAlON component phase. In general, for samples synthesized from nano-sized amorphous Si3N4, which were almost fully dense, containing >95% β′-SiAlON, the hardness values were 13.4–13.8 GPa with a fracture toughness of 3.5–4.6 MPa m1/2. For equivalent samples synthesized from micro-sized β-Si3N4, hardness was in the range 13.9–14.4 GPa with a fracture toughness of 4.3–4.5 MPa.m1/2. These values are comparable with fully dense β′-SiAlONs, usually containing intergranular glass phase which has been sintered by HIP and other processes at much higher temperatures for longer times.

This study investigates the influence of heating rate on the tribological and corrosion properties of 52100 bearing steel samples consolidated via spark plasma sintering. The consolidation was conducted at different heating rates of 50, 100, 200, 300, and 400 °C/min and the thermomechanical properties of the resulting samples were characterized. Ball-on-disc tribological tests and electrochemical techniques were used to evaluate the wear and corrosion resistance, respectively. The results showed that an increased heating rate positively affects the thermomechanical and tribological properties of 52100 bearing steel. The sintered samples exhibited a low coefficient of friction (between 0.4 and 0.56) and a low wear rate (between 1.4 and 1.8 × 10−6 mm3/Nm) at heating rates between 100 and 400 °C/min. Furthermore, the corrosion resistance of the samples gradually drops above the heating rate of 100 °C/min. The samples can be ranked in the order of decreasing corrosion resistance thus: 100 > 200 > 300 > 400 > 50 °C/min. The improved corrosion resistance of the sample sintered at 100 °C/min can be attributed to its refined crystal size and high density.

In this study, three different methods, namely, selective laser melting (SLM), spark plasma sintering (SPS), and casting techniques, were utilized to fabricate nickel alloy 718 samples. The effects of the fabrication methods on the mechanical and thermal properties of the samples were evaluated and correlated to the developed microstructure. All three methods produced samples with dense microstructure and high structural integrity. The choice of the fabrication method significantly affected the properties of nickel alloy 718. The SLM process provided highly compacted samples with high hardness values compared with those offered by the other two techniques. However, the SPSed sample fabricated at 1000 °C showed a higher thermal expansion (13.9 ppm K−1) than did the SLM and cast samples. The SPS temperature of 1000 °C was found to be optimum as a decrease in the SPS temperature to 900 °C resulted in a considerable reduction in the density. Moreover, samples produced by melting at 1450 °C and cast sample showed the highest thermal conductivity (10.3 W/m·k) amongst the samples.

Zincite (ZnO) nanoparticles are prepared by adopting reflux assisted co-precipitation method. Prepared product is subjected to different instrumental techniques to investigate its morphology and lattice structure. Rietveld refinements are performed on XRD results and values of various lattice parameters are calculated and structural model of ZnO is predicted. The morphology of the product is analyzed with the help of scanning and transmission electron microscopies (SEM and TEM). The size of prepared nanoparticles is in the range of 80–100 nm where as some larger particles having irregular morphology with size up to 1 μm are also observed in the product. Prepared product is also used as fuel additive and its effect on different fuel parameters is studied. The combustion characteristics (flash and fire point) and physical characteristics (cloud and pour point, kinematic viscosity and specific gravity) of fuel are studied in the presence of 10, 15 and 20 ppm dosage of additive. ZnO is used as nanoadditive for enhancing concrete durability. Concrete pellets are formed with different dosage (0, 0.1, 0.5, 1.5 w/w%) of nanoadditive. Ratio of cement, sand and nanoadditive is kept as 33:66:1 respectively in all concrete samples with constant amount of water. Effect of nanoadditve is studied on different properties of cement such as aging, porosity, compressive strength, specific heat, thermal conductivity and thermal diffusivity. ZnO nanoadditive is found to be effective in modulating both mechanical and thermal properties of concrete samples.

The emergence of a pandemic scale respiratory illness (COVID-19: coronavirus disease 2019) and the lack of the world's readiness to prevent its spread resulted in an unprecedented rise of biomedical diagnostic industries, as they took lead to provide efficient diagnostic solutions for COVID-19. However, these circumstances also led to numerous emergency use authorizations without appropriate evaluation that compromised standards, which could result in a larger than usual number of false-positive or false-negative results, leading to unwanted ambiguity in already confusing realities of the pandemic-hit closures of the world economy. This review is aimed at comparing the claimed or reported clinical sensitivity and clinical specificity of commercially available rapid antibody diagnostics with independently evaluated clinical performance results of the tests. Thereby, we not only present the types of modern antibody diagnostics and their working principles but summarize their experimental evaluations and observed clinical efficiencies to highlight the research, development, and commercialization issues with future challenges. Still, it must be emphasized that the serological or antibody tests do not serve the purpose of early diagnosis but are more suitable for epidemiology and screening populaces with an active immune response, recognizing convalescent plasma donors, and determining vaccine efficacy.

Aiming for the rapid fabrication of robust catalytic materials, we herein present rhodium sulfide (Rh2S3) thin films with high activity for the hydrogen evolution reaction (HER) in water splitting. A single-step aerosol-assisted deposition using a rhodium diethyldithiocarbamate precursor was employed for this purpose at an operating temperature of 500 °C. Manipulating only the deposition time yielded crystalline and phase-pure Rh2S3 films with self-organized and controllable nanostructured morphologies. The HER performance of the resulting films in acidic electrolyte was found to be largely influenced by these morphologies in addition to the metallic substrates (i.e., Ni foam (NF) and Ti foil (Ti)) used to form the working electrodes in an electrolytic cell. A blooming flower-like structure obtained in 80 min of deposition on a NF substrate (Rh2S3/NF-80) exhibited the highest catalytic activity. A detailed characterization indicated that the highly exposed surface characters and pronounced number of active sites were responsible for such an extraordinary performance. To produce current densities of 10 and 100 mA cm−2, the Rh2S3/NF-80 needed overpotentials (η) of 67 and 132 mV, the lowest reported for any rhodium sulfide material, while being comparable to the Pt benchmark catalyst. The Tafel slope for Rh2S3/NF-80 electrode was estimated to be 36 mV dec−1, suggesting that the HER followed the Volmer–Heyrovsky kinetic model. Furthermore, the current density outstretched to 350 mA cm−2 at an overpotential of just above 300 mV, thereby meeting the standards for large-scale application. With all these unprecedented structural and performance attributes, it is envisaged that the as-prepared Rh2S3 catalytic films would perform equivalently in many other catalytic operations.

This study attempt to investigate microstructural, thermomechanical and tribological properties of low-temperature sintered cBN and Ni-coated cBN reinforced bearing steel composites. Ultrasonic probe sonication and spark plasma sintering (SPS) at 900 and 1000 °C were utilized for the dispersion and consolidation, respectively. Findings show that up to 30 wt.% addition of cBN particles, no significant effect on the thermal properties, for the selected sintering temperatures. However, the introduction of Ni-coated cBN reinforcement caused a considerable impact on thermomechanical properties. The developed composites exhibited improved tribological properties as compared to the unreinforced bearing steel. Similarly, samples sintered at a higher temperature of 1000 °C possessed enhanced wear resistance in comparison to samples sintered at 900 °C. Furthermore, Ni-coated cBN reinforced samples exhibited superior wear resistance. However, more than 10wt.% of Ni-coated cBN reinforcement led to material loss, whereby some of the Ni melted out from the consolidated composite during the sintering process.

Bimetallic catalysts due to the synergistic effects often outperform their single-component counterparts while exhibiting structure and composition-dependent enhancement in active sites, thereby having the potential to improve the current density and over-potential parameters in the water oxidation reaction. Herein, we demonstrate a simple and rapid, yet highly efficient method to fabricate Pd–CoO films of immaculate homogeneity as characterized using different imaging and spectroscopic techniques. The SEM images revealed that the films were composed of bimetallic spherical granules wherein both metals were uniformly distributed in an atomic ratio of ~ 1:1. The time-dependent investigations of the film fabrication behavior demonstrated that the films formed in shorter deposition times (1–2 h) display more porous character, allowing better access to the reaction centers. This character was transcribed into their enhanced electrocatalytic performance toward the oxygen evolution reaction (OER). Using this specific bimetallic formulation, we could attain a low over-potential of 274 mV for a current density of 10 mA cm−2, whereas the high current density value of > 200 mA cm−2 was achieved while still under 600 mV of over-potential. The cycling and current generation stability was also found to be sufficiently high, which can only be attributed to the facile electron transfer processes and a higher number of active sites available in homogeneous bimetallic films.

The surface of implant materials is one of the most significant factors for controlling the interaction between biomaterials and bone tissues. Hence, enhancing the clinical performance of bio-implants is being widely focused worldwide. Herein, we report that nanostructured silver (Ag) coatings prepared on medical grade 316L stainless steel (SS) substrates are promising implant/surgical materials for orthopedic applications. Homogeneous nanoparticle-shaped silver thin films as a function of growth time (15 to 60 minutes) were developed at a temperature of 450 °C through aerosol-assisted chemical vapor deposition (AACVD) using a silver (I) acetate solution. All silver films were characterized using various surface and structural analysis techniques to confirm the phase and stoichiometric purity of the coating. Scanning electrochemical microscopy experiments were conducted to inspect the initial degradation of silver films on 316L SS substrates in simulated body fluid (SBF). Corrosion assessments in the SBF medium indicated that all the coated 316L SS substrates under study exhibited higher corrosion resistance than the uncoated ones; in particular, Ag films grown in 30 minutes showed the highest corrosion resistance among the other silver coatings produced under different conditions. The better corrosion performance of the Ag-30 sample was attributed to the dense, compact silver layer obtained in 30 minutes of deposition utilizing the AACVD technique.

While the noble metals (e.g., platinum, (Pt)) remain the benchmark electrocatalyst for the hydrogen evolution reaction (HER), their mass production require a reduced metal loading and faster fabrication protocols. The aim of the present work is to prepare Pt thin films by simple and fast fabrication technique, and to evaluate their performance for HER. The thin films of Pt are grown on two substrates, namely titanium foil (Ti) and nickel foam (NF), using a single step aerosol assisted chemical vapor deposition (AACVD) method. The film deposition time are varied from 20 to 60 min. Microscopic analyses suggest a gradual evolution of the films into percolated and/or porous nanostructures, a feature that remains highly desired to allow the maximum access of active sites. The performance of the as-prepared electrodes is evaluated by monitoring the HER in acidic electrolyte. The Pt film on nickel foam (Pt/NF) exhibits better electrical conductivity and smaller charge transfer resistance, while the film deposited on the Ti foil (Pt/Ti) demonstrates superior catalytic activity per active sites. The as-prepared Pt/Ti and Pt/NF electrodes produce 10 mA cm−2 at overpotential of 28 mV and 26 mV, respectively, better in performance than commercial Pt/C electrode (~39 mV), set a new bench mark electrocatalyst for the HER.

The 3D architecture of Co(II) oxide (CoO) having oxygen defects has been recognized as a highly functional characteristic towards efficient electrocatalysis of water. Herein, different surface structures of CoO in the form of chemically deposited films were fabricated via AACVD technique, directly over the transparent fluorine-doped tin oxide (FTO) electrodes just by varying the deposition times. The as-prepared films were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). As the deposition time is varied, the surface structure of the CoO changes from nanoparticles that are formed just in 15 min to nanobuds at 30-min deposition, and finally to a homogeneously distributed dense population of nanoflowers in 45 min. The evolution of these structures was also accompanied by a preferential exposure of (111) facets and an increasing number of oxygen defects which resulted in an enhancement of electrocatalytic activity towards water oxidation. The CoO nanoflowers (CoO-NFs) with highest number of these active oxygen vacancies showed the best performance with an overpotential of 325 mV vs RHE for a current density of 10 mA/cm2 while having a Taefl slope of 98 mV/dec, a mass activity of 35.2 A/g, and the electrochemically active surface area (ECSA) of 1069 μF. However, more importantly, the current density for CoO-NF jumped sharply to the values above 200 mA/cm2 with potential less than 1.8 V vs RHE, thereby meeting the commercialization standards while still providing high stabilities of oxygen generation, current densities, and repeated cycling. Such a performance can be considered remarkable for a material fabricated via a rapid and facile synthetic route and is directly deposited on a low cost and relatively less conductive FTO substrate which can be attributed to the synergistic effect of the larger specific surface area of 3D structure and the high distribution of oxygen defects.

The aim of the present study is to produce high performance Pd-based electrodes for water splitting by a simple and fast preparation technique, and to investigate the impact of substrates and film growth time on electrode performance. The electrodes are prepared in one step by the aerosol-assisted chemical vapor deposition (AACVD) method within 30 to 120 min. Pd is deposited on titanium (Ti) foil and nickel foam (NF). Microscopic analyses indicate the growth of cauliflower-like porous nanostructures of Pd. Electrochemical measurements indicate that the Pd/NF electrode requires only 65 mV and 189 mV, while the Pd/Ti electrode requires 121 mV and 288 mV to produce current densities of 50 and 150 mA cm−2, respectively, for the hydrogen evolution reaction (HER). The respective Tafel slopes for Pd/NF and Pt/Ti are determined to be 29.3 mV dec−1 and 52.3 mV dec−1, suggesting different rate-determining mechanisms of the HER on various substrate surfaces. The better activity of the Pd/NF electrode is attributed to higher electrical conductivity of bare NF and Pd/NF electrodes compared to that of bare Ti and Pd/Ti electrodes, though the charge transfer resistances are discerned to be comparable. The turnover frequency of the Pd/NF electrode is superior to that of Pd/Ti at lower overpotential, which becomes comparable with increasing potential. The results of this study combined with our earlier findings reveal the bi-functional electrocatalytic nature of the nanoscale Pd for possible utilization in an electrochemical water splitting unit for H2 and O2 production.

The fabrication of smart, efficient, and innovative devices critically needs highly refined thin-film nanomaterials; therefore, facile, scalable, and economical methods of thin films production are highly sought-after for the sustainable growth of the hi-tech industry. The chemical vapor deposition (CVD) technique is widely implemented at the industrial level due to its versatile features. However, common issues with a precursor, such as reduced volatility and thermal stability, restrict the use of CVD to produce novel and unique materials. A modified CVD approach, named aerosol-assisted CVD (AACVD), has been the center of attention due to its remarkable tendency to fabricate uniform, homogenous, and distinct nano-architecture thin films in an uncomplicated and straightforward manner. Above all, AACVD can utilize any custom-made or commercially available precursors, which can be transformed into a transparent solution in a common organic solvent; thus, a vast array of compounds can be used for the formation of nanomaterial thin films. This review article highlights the importance of AACVD in fabricating heterobimetallic oxide thin films and their potential in making energy production (e. g., photoelectrochemical water splitting), energy storage (e. g., supercapacitors), and environmental protection (e. g., electrochemical sensors) devices. A heterobimetallic oxide system involves two metallic species either in a composite, solid solution, or metal-doped metal oxides. Moreover, the AACVD tunable parameters, such as temperature, deposition time, and precursor, which drastically affect thin films microstructure and their performance in device applications, are also discussed. Lastly, the key challenges and issues of scaling up AACVD to the industrial level and processing for emerging functional materials are also highlighted.

Dopamine (DA) is an important neurotransmitter, which is created and released from the central nervous system. It plays a crucial role in human activities, like cognition, emotions, and response to anything. Maladjustment of DA in human blood serum results in different neural diseases, like Parkinson's and Schizophrenia. Consequently, researchers have started working on DA detection in blood serum, which is undoubtedly a hot research area. Electrochemical sensing techniques are more promising to detect DA in real samples. However, utilizing conventional electrodes for selective determination of DA encounters numerous problems due to the coexistence of other materials, such as uric acid and ascorbic acid, which have an oxidation potential close to DA. To overcome such problems, researchers have put their focus on the modification of bare electrodes. The aim of this review is to present recent advances in modifications of most used bare electrodes with carbonaceous materials, especially graphene, its derivatives, and carbon nanotubes, for electrochemical detection of DA. A brief discussion about the mechanistic phenomena at the electrode interface has also been included in this review.

Polysulphone (PSU) composites with carbon nanotubes (PSU-CNT) and graphene nanoplatelets (PSU-GNP) were developed through the solution casting process, using various weight load percentages of 1, 3, 5, and 10 wt% of CNT and GNP nanofillers. The microstructural and thermal properties of the PSU-based composites were compared. The microstructural characterisation of both composites (PSU-CNTs and PSU-GNPs) showed a strong matrix–filler interfacial interaction and uniform dispersion of CNTs and GNPs in the PSU matrix. The analysis demonstrated that both the thermal conductivity and effusivity improved with the increase in the weight percentage (wt%) of CNTs and GNPs because of the percolation effect. The polysulphone-based composite containing 10 wt% CNTs showed a remarkably high thermal conductivity value of 1.13 (W/m·K), which is 163% times higher than pure PSU. While the glass transition temperature (Tg) was shifted to a higher temperature, the thermal expansion was reduced in all the PSU-CNT and PSU-GNP composites. Interestingly, the CNTs allowed homogeneous distribution and a reasonably good interfacial network of interaction with the PSU matrix, leading to better microstructural characteristics and thermal properties than those of the PSU-GNP composites. The findings highlight the importance of controlling the nature, distribution, and content of fillers within the polymeric matrix.

Currently, there is a rising demand to develop composite materials with outstanding tribological properties along with excellent thermal-mechanical properties for harsh tribological applications. In view of this demand, the tribological behaviour of spark plasma sintered (SPS) nano-alumina (∼150 nm)-based composites reinforced with 10, 20 and 30 wt.% uncoated and nickel-coated cubic boron nitride (cBN) particles was evaluated using a ball-on-disc configuration against three different counterface materials (WC, Si3N4 and Al2O3) under dry sliding conditions. A variety of techniques were used to evaluate the phase composition and to study the dispersion, wear behaviour and wear mechanisms. The nano-alumina composites exhibited improved wear resistance and coefficient of friction (COF). These results were attributed to the unique combination and uniform dispersion of the reinforcing particles within the composites. Moreover, Ni-coated cBN particles displayed high wear resistance, primarily due to the excellent interfacial bonding provided by the nickel coating. The wear resistance of the sample reinforced with 30% cBN-Ni was improved by at least 85%. The wear mechanisms involved during sliding wear were abrasion, matrix grain pullout (dislodgement of matrix material), microcracking, chipping, and tribolayer formation. Keywords: Alumina nanocomposites, Cubic boron nitride, Microstructural analysis, Wear, Tribophysics

Water oxidation catalysis is gaining more attention in recent times owing to its potential for solar and chemical energy conversion and for green fuel generation. The overwhelming hurdle in this quest is to develop a noble‐metal‐free, efficient, low overpotential water oxidation electrocatalyst exhibiting tremendous stability and to be obtained from earth‐abundant materials. We show here unique copper‐based water oxidation electrocatalyst derived from thin film Cu‐colloidal nanoparticles and is highly efficient, robust for water oxidation. The catalyst advantageously exhibits nanobeads and nanorods type mixed morphological features with narrow size distribution. The onset for oxygen evolution reaction occurs at a small potential of 1.45 VRHE (η=220 mV) which is the lowest observed relative to other copper‐based materials. The catalyst also maintains remarkable stability during long‐term water electrolysis experiments. Moreover, the catalyst shown to exhibit a high electroactive area with a Tafel slope of 52 mV dec1‐, high TOF of 0.81 s1‐ and mass activity of 87 mA mg‐1. Copper is an interesting material because it can also serve as CO2 reduction catalysts at the cathode side. The straightforwardly prepared, handy, and inexpensive Cu‐based electrocatalytic system is a flexible catalyst for electrooxidation of water and for chemical energy conversion and is an attractive alternative to Pt, Ir, and Ru based electrocatalysts obtained from expensive resources and tedious methods.

A facile and cost effective AACVD procedure for the synthesis of platinum thin films has been reported using newly synthesized Pt-dialkyldithiocarbamate complexes, [Pt(S2CNR2)] (where R = isobutyl, iBu (1); benzyl, Bz (2)), as single source precursors. The structural characterization of the dithiocarbamate complexes has been performed by single crystal X-ray diffraction, 1H and 13C NMR, FT-IR and thermogravimetric analysis. The structure, composition, and morphology of the resulting Pt-films is established through XRD, XPS, EDX and FE-SEM analyses. The catalytic performance of the as-synthesized Pt-films is evaluated by using them as counter electrodes in dye sensitized solar cells as an example application. The efficiency of the AACVD produced electrodes is found to be better than conventionally used Pt-counter electrodes made from the doctor blade’s method. It is also demonstrated that films having a well-connected and defect free surface topography show better catalytic performance, which is due to their high conductivity and reflectivity. Thus a simple and low cost method employing dithiocarbamate precursors is manifested to be immensely efficient in generating Pt-films and electrodes of tremendous applicability.

Aerosol-assisted chemical vapor deposition (AACVD) is successfully implemented for the fabrication of nanostructured palladium (Pd) thin films on FTO substrate. The Pd films are produced using a commercially available precursor palladium acetylacetonate (Pd(C5H7O2)2) under the flow of N2 gas without incorporating hydrogen gas or any other reducing agent. This synthetic strategy can effectively confront the previous problems related with conventional CVD approach while depositing palladium thin films such as reduced volatility and thermal instability of precursors. The palladium thin films were characterized by powder X-ray diffraction (pXRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) analysis. Hydrazine is a colorless and flammable chemical routinely used in rocket fuel, agro-chemicals, textile dyes, and as corrosion inhibitors in various industries. However, hydrazine is a toxic and highly carcinogenic chemical. The newly fabricated palladium nanostructured films were tested for electrochemical sensing of hydrazine in this study. A highly stable and reproducible amperometric response for hydrazine oxidation was obtained with a superior limit of detection (LOD) of 10 nM, and limit of quantification (LOQ) of 33 nM while the sensitivity value calculated was 2.94 μA μM−1 cm−2. A linear concentration range of 1–325 μM was achieved by chronoamperometry.

An improved and facile aerosol-assisted chemical vapor deposition (AACVD) process for the production of palladium thin film on indium tin oxide (PdNP-ITO) electrodes was described and applied for the electrochemical detection of hydrogen peroxide (H2O2). The detailed characterization of the films by X-ray diffraction (XRD), scanning electron microscopy/energy-dispersive X-ray (SEM/EDX) spectroscopy, and X-ray photoelectron spectroscopy (XPS) analysis proved the high crystallinity and phase purity of the nanosized metallic palladium films without the evolution of any elemental impurities from the precursor compound. The as-prepared electrodes were used for nonenzymatic amperometric H2O2 detection via electrochemical reduction. The LOD was 40.8 nM with a high sensitivity of 760.84 μA/(μM cm2). From the experimental scan rate variation analysis, the reduction of H2O2 on the PdNP-ITO electrode surface was determined to be adsorption controlled. For this process of adsorption, we calculated the number of elect...

There is an overwhelming desire to discover new catalytic materials for efficient water oxidation that perform at low overpotentials (below 1.50 V vs. RHE), and which exhibit tremendous stability along with high oxygen evolution reaction (OER) current density over a small potential window. However, it remains a challenge to establish a competent solar to fuel conversion system. We present here the first example of a nanoscale nanoporous Pd-derived benchmark material used as a highly stable and low overpotential electrocatalyst for water oxidation. The Pd electrocatalyst executes water oxidation at an onset potential of just 1.43 V vs. RHE; η = 200 mV. The catalyst also exhibits remarkable performance for OER, reaching a current density of 10 mA cm−2 at 1.47 V (η = 240 mV), and with a current density of 100 mA cm−2 achieved at only 1.63 V (η = 400 mV), which represents better OER activity than that of the benchmark IrO2 electrocatalyst (301 mV and 313 mV required to drive a current density of 10 mA cm−2). Furthermore, the catalyst demonstrates a Tafel slope of 40 mV dec−1, a high mass activity of 560 mA mg−1 (MA) and a large TOF value of 0.2 s−1, and exhibits remarkable long-term stability for use in oxygen evolution experiments. A thin-film Pd electrocatalyst was obtained via the Aerosol-Assisted Chemical Vapor Deposition (AACVD) method on conducting surfaces. XRD and XPS analyses showed a phase-pure crystalline metallic Pd deposit. A surface morphology study revealed a nanoparticulate highly porous nanostructure. Our study reveals a straightforward method for the development of the first example of a Pd-derived nanoporous electrocatalyst for high-efficiency water oxidation and for chemical energy conversion.

Herein, we report the fabrication of NiO–CoO films for the electrochemical detection of hydrazine. An electrochemical sensor was devised where aerosol assisted chemical vapor deposition (AACVD) was employed as a nifty method for synthesizing NiO–CoO films over FTO electrodes. NiO–CoO-nanoparticle (NP) and NiO–CoO-nanowall (NW) films were fabricated over FTO substrates. The electrocatalytic analysis was performed in a standard three-electrode electrochemical setup. NiO–CoO-NW/FTO showed enhanced electro-oxidation for hydrazine at all concentrations tested. XRD, XPS, EDX, and FE-SEM techniques were used to characterize the structural, morphological, and elemental properties of NiO–CoO films. The results showed improved sensitivity, a large dynamic range, and good long-term stability of NiO–CoO-NW films. The amperometric response was used to measure the detection limit, and it was as low as 0.01 μM, and the sensitivity is ∼33 μA μM−1 cm−2. Besides, the NiO–CoO-NW/FTO electrodes showed significant selectivity towards hydrazine upon testing cross-sensitivity to other common interfering molecules. This strategy of using NiO–CoO-NW/FTO electrodes prepared via AACVD has great potential for the direct determination of hydrazine in environmental sensing applications.

Fluorine doped tin oxide (FTO) substrates were deposited with thin metallic nickel films, having distinguishable surface morphologies, via a rapid, facile, and scalable approach i.e., aerosol assisted chemical vapor deposition (AACVD). The growth patterns of the nickel deposits were studied, showing a coalescing behavior as a function of the deposition time in a hierarchical fashion. These studies were followed by electrochemical measurements to design an efficient sensor for formaldehyde detection. The electrochemical responses were correlated with the surface characteristics of the films, whereas the optimized parameters were subjected to the evaluation of sensing performances. The developed sensor demonstrated a detection limit of 8.3 × 10-6 M and a sensitivity of 0.18 A M-1 within a linear range of 0-6.5 mM. Further, the sensor showed a response time of less than 5 s, selectivity against similar concentrations of methanol and formaldehyde, and recovery of ∼102% in a spiked fruit juice sample. Finally, the commercial viability of the fabrication procedure is tested using batch production analysis, and the high reproducibility of the data shows a promising future in mass production. It is envisaged that such low-cost fabrication procedures can be converted into many useful applications in the future.