The development of efficient electrocatalysts based on Pt-free materials is a crucial step for the maturation of competitive water splitting technologies able to sustain the upcoming hydrogen-based ...economy. In this context, the present work optimizes a codeposition/annealing methodology to produce electrocatalytic layers for the hydrogen evolution reaction (HER) based on one of the most promising alternatives to Pt-based catalysts: nickel phosphides. A nickel–phosphorus solid solution is codeposited with red phosphorus microparticles and the obtained composites are annealed to promote interdiffusion and reaction between nickel and phosphorus. The experimentation carried out demonstrates that the properties of the final phosphide layers depend on the conditions employed in both the codeposition step and the annealing step. It is fundamental to evaluate and optimize the NiP/P codeposition process, and it is also important to understand the influence of annealing time and temperature on the microstructure and HER performance of the layers obtained. X-ray photoelectron spectroscopy (XPS) is employed to evaluate the phase composition at the surface, highlighting the presence of a top layer characterized by a Ni
2
P/Ni
12
P
5
ratio significantly lower than the value found in the bulk of the coating. Annealed NiP/P layers are tested for HER in 0.5 M sulphuric acid solution. The tests demonstrate a clear correlation between the Ni
2
P/Ni
12
P
5
ratio on the surface and the overpotential for HER. Coherently, when the outer Ni
12
P
5
-rich layer is mechanically removed, lower overpotentials are observed (169.5 mV vs. RHE for 10 mA cm
−2
).
Inkjet printing is a versatile and cheap technique for the fabrication of films, offering unique advantages in terms of scalability, precision, and customization. In recent years, there has been a ...growing interest in utilizing inkjet printing technology for the deposition of magnetic films with tailored properties. Cobalt ferrite (CoFe2O4) stands out due to its exceptional magnetic properties, including high coercivity, saturation magnetization, and excellent chemical stability. This paper presents a comprehensive study on the inkjet printing of cobalt ferrite magnetic films, focusing on the manufacturing process, especially on the different factors that could lead to stable multilayer depositions to achieve high thicknesses: ink solid loading, drop spacing, substrate temperature, and interlayers drying. Finally, the microstructure of the samples is investigated to identify the occurring defects after sintering between 800 and 1000 °C. The magnetic properties of the films are determined, revealing a maximum coercivity of 1.98 kOe and a magnetic saturation of 78.25 emu cm−3.
Cobalt ferrite films produced via inkjet printing exhibit exceptional magnetic properties, including high coercivity and saturation magnetization. This study explores how factors like ink composition, drop spacing, and sintering temperatures affect film quality and properties. Findings reveal the feasibility of creating stable, multilayer films with high coercivity and saturation magnetization, highlighting the potential of inkjet for complex magnetic pattern fabrication.
In the present work, Cu2ZnSnS4 (CZTS) thin films were successfully prepared using a co-electrodeposition–annealing route, in which Cu-Zn-Sn metal precursors were deposited by a novel electrolyte ...formula on Mo substrate, followed by annealing in elemental sulfur environment in quartz tube furnace with N2 atmosphere. Morphological, compositional and structural features of the films were investigated using scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction before and after sulfurization. Raman spectroscopy was performed after sulfurization to fully characterize the deposited films. Glow discharge optical emission spectroscopy (GDOES) has also been carried out to see how composition changes along the film thickness. Results confirmed that kesterite structure of CZTS has been well formed after sulfurization of the film. It was also observed that CZTS properties depend on annealing times and ramping rate during sulfurization.
In this paper, the innovative fabrication process for electro-mechanical sensors, born from the smart combination of 3D-printing and wet-metallization and previously demonstrated in a ...<inline-formula> <tex-math notation="LaTeX">z </tex-math></inline-formula>-axis accelerometer, is employed to fabricate a fully 3D three-axis accelerometer. Thanks to the three-dimensionality of the printing process, a central symmetry along the three axes can be obtained by design, unlike in common 2D-like microfabrication processes. Electrostatic differential sensing is obtained through the metallization procedure and the subsequent mounting of fixed electrodes on an external frame of the mechanical structure. Experimental tests under accelerations show good agreement with theoretical predictions. With relatively small dimensions (features as low as <inline-formula> <tex-math notation="LaTeX">450~\mu \text{m} </tex-math></inline-formula>), very high capacitive sensitivity (> 200 fF/g) and low theoretical thermo-mechanical noise, the proposed three-axis accelerometer represents a further step towards the development of an innovative fabrication process for high-performance, customizable, and low-cost electro-mechanical devices.
Many researches have been devoted to rechargeable power generators that can store (but also release) energy. This availability is ensured through (e. g.) the oxygen evolution reaction (OER). However, ...(i) large values of the overpotentials and (ii) a progressive detriment of the anode (graphite) electrode limit the ultimate device. In view of enhancing the electrode performances, graphite was protected by following different strategies, which oblige to follow precise preparation protocols.
Here, we prove that a thin layer of free‐base porphyrin molecules is able to protect the underneath graphite electrode from detriment even if many (about 100) electrochemical cycles are performed.
In this paper, additive manufacturing and wet metallization process are combined to fabricate three prototypes of differential electro-mechanical z-axis accelerometers. The smart combination of ...existing fabrication processes makes the proposed fabrication flow unique in the sensors field. The mechanical design of the three proposed devices exploits the threedimensionality of the 3-D-printing technique and the electrostatic differential readout is allowed thanks to the wet-metallization process of the printed structure. Experimental measurements show a very good agreement with theoretical predictions thus proving a good reliability of the proposed design flow and fabrication process. With their relative small footprints (minimum dimension in the order of hundreds of μm), good performances (sensitivity >12 fF/g, sub % linearity error up to 11 g of full scale and theoretical noise estimation of few tens of ng/√Hz) and high customizability, they represent an important step toward novel application fields of inertial sensors.
Current evidence suggests that at least part of the cardioprotective benefits of consumption of long-chain n-3 polyunsaturated fatty acids (PUFAs) relates to their incorporation into the ...phospholipids of cardiac cell membranes. Dietary supplementation with purified extracts of n-3 PUFAs derived from fish oil rapidly alters the composition of fatty acids in blood cell membranes and in other tissues. The present review summarises the time-course and dose-dependent incorporation and washout of n-3 PUFAs in the clinical setting and discusses the implications of these pharmacokinetic data in terms of biological effects.
In the present work the electrodeposition of zinc-nickel alloys with 15-20 wt.% nickel from non-aqueous solutions based on ethylene glycol is investigated. Potentiostatic deposition conditions are ...used, which are found to offer optimal coating quality and superior control over composition. In addition, ammonium chloride is evaluated as additive to partially suppress zinc incorporation into the deposit and to enhance layer quality. Layers composition, surface morphology of the deposits and their anticorrosive properties are investigated. The electrochemical characteristics of the Zn-Ni electrolytes are studied using cyclic voltammetry measurements. From the phase composition point view, X-ray diffraction results confirm that a metastable γ phase is present in the as deposited Zn-Ni alloys with nickel content 16-18 wt.%. Corrosion tests show that the barrier behaviour against corrosion of Zn-Ni films electrodeposited from the NH4Cl containing bath is superior in comparison to layers plated from an additive-free bath. The use of the additive enlarges the grains and provides a compact surface structure, which upskills the anticorrosive behaviour of the deposit.
PDF
