One-pot synthesis of crystalline structure: Nickel-iron phosphide and selenide for hydrogen production in alkaline water splitting

Electrocatalytically active nanocomposites play a vital role in energy generation, conversion, and storage technologies. Transition metal-based catalysts such as nickel and iron and their pnictide (phosphide), and chalcogenide (selenide) compounds exhibit good activity for hydrogen evolution reaction (HER) in the alkaline environment. In this study, transition metals-based catalysts (Ni-P-Se, Fe-P-Se, and Ni-Fe-P-Se) solutions were prepared using a simple one-pot method. Prepared solutions were deposited on Ni foam, and different characterization techniques were used to determine the composition, structure, and morphology of as-prepared catalysts. Furthermore, it was found that Ni-Fe-P-Se as a cathode material showed better HER performance compared to other investigated materials with the overpotential value of 316 mV at 10 mA cm-2 current density and 89 mV dec-1 Tafel slope value. The stability tests of the as-prepared catalyst confirmed that the synergistic effect between various elements enhances the electrocatalytic performance for up to 24 hours, providing a fair, stable nature of Ni-Fe-P-Se based sample

Ion Beam Effect on the Structural and Optical Properties of AlN:Er

Erbium (Er)-doped Aluminum Nitride (AlN) thin films were deposited and fabricated on Si (100) and Si (111) substrates in a Nitrogen atmosphere using the plasma magnetron sputtering technique. The deposited and fabricated thin films were thermally annealed at 900 °C in Argon (Ar) atmosphere. The samples were irradiated with protons at a dose of 1 × 1014 ions/cm2 which carried an incident energy of 335 keV, using a tandem pelletron accelerator. Rutherford backscattering spectroscopy (RBS) and X-ray diffraction (XRD) were used for the stoichiometric and structural analysis of the films, while Fourier transforms infrared spectroscopy (FTIR) was performed to track the changes in the optical characteristics of thin films before and after the ions’ irradiation and implantation. The irradiation has affected the optical and structural properties of the films, which could be exploited to use the AlN:Er films for various optoelectronic and solid-state device applications

Structural and Electronic Properties of (HfH2)(n) (n=5-30) Clusters: Theoretical Investigation

Metallic hydride clusters have greater importance due to its unique physicomechanical properties. For solid-state hydrogen storage, (HfH2)(n) clusters has been considered a promising candidate because of high hydrogen capacity, low cost and larger interacting affinity between atoms. The structural and electronic properties of (HfH2)(n), clusters are investigated by employing the density functional theory. From the DFT calculations, it is found that Hf atom occupies central position while H atoms tends to occupy at vertex spots. Through structural stability analysis, the calculated binding energy and second order energy difference of (HfH2)(n) clusters increases from (HfH2)(5) through (HfH2)(30). The charge density distribution and results of Bader analysis revealed ionic bonding character between Hf and H atoms and transfer of electrons is observed from Hf to H atoms. The orbital overlapping contribution of the interacting Hf and H atom is also performed

Electrochemical performance of grown layer of Ni(OH)2 on nickel foam and treatment with phosphide and selenide for efficient water splitting

Active nanocomposites synthesized by the electrochemical approach play a vital role in energy generation, conversion, and storage technologies. Recently, scientists began to explore the use of earth-rich transition metalbased materials to replace precious metal-based catalysts. Transition metals (TMs) based nickel (Ni) and their pnictides compounds such as phosphides and selenides exhibit good activity for hydrogen evaluation reaction (HER) and the entire water electrolysis process. In this study, we first prepared Ni(OH)2 and grown its layer on Ni foam (NF) and treated it with selenide (Se) and phosphide (P) then nickel-based selenide-phosphide catalyst (Ni-P-Se) was prepared by simultaneous selenization and phosphidation process for the first time. The asobtained composite was then analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), elemental mapping and transmission electron microscope (TEM) means to study the composition, structure, and micro-morphology of materials. Furthermore, we also observed electrocatalytic water splitting activity using electrochemical cell. The results of electrochemical tests depicted that the selenization and phosphidation treatments significantly enhanced the electrocatalytic HER activity of the starting materials. The overpotentials required for Ni-P-Se to reach 10 mA cm-2 and 100 mA cm-2 were only 242 mV and 282 mV. The Tafel slope of Ni-P-Se is 151 mV dec-1, which is lower than that of nickel phosphide, selenide, and hydroxide indicating that selenide-phosphide enhances the HER reaction kinetics of the material, which in turn increases hydrogen output rate as compared with previous studies

Electrochemical performance of grown layer of Ni(OH)2 on nickel foam and treatment with phosphide and selenide for efficient water splitting

Active nanocomposites synthesized by the electrochemical approach play a vital role in energy generation, conversion, and storage technologies. Recently, scientists began to explore the use of earth-rich transition metalbased materials to replace precious metal-based catalysts. Transition metals (TMs) based nickel (Ni) and their pnictides compounds such as phosphides and selenides exhibit good activity for hydrogen evaluation reaction (HER) and the entire water electrolysis process. In this study, we first prepared Ni(OH)2 and grown its layer on Ni foam (NF) and treated it with selenide (Se) and phosphide (P) then nickel-based selenide-phosphide catalyst (Ni-P-Se) was prepared by simultaneous selenization and phosphidation process for the first time. The asobtained composite was then analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), elemental mapping and transmission electron microscope (TEM) means to study the composition, structure, and micro-morphology of materials. Furthermore, we also observed electrocatalytic water splitting activity using electrochemical cell. The results of electrochemical tests depicted that the selenization and phosphidation treatments significantly enhanced the electrocatalytic HER activity of the starting materials. The overpotentials required for Ni-P-Se to reach 10 mA cm-2 and 100 mA cm-2 were only 242 mV and 282 mV. The Tafel slope of Ni-P-Se is 151 mV dec-1, which is lower than that of nickel phosphide, selenide, and hydroxide indicating that selenide-phosphide enhances the HER reaction kinetics of the material, which in turn increases hydrogen output rate as compared with previous studies