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Hydrogen fuel is a non-toxic and source-abundant energetic system, but for its applications in the industry, several issues related to its storage must be resolved. Compounds like NaBH 4 appear as promising hydrogen sources, while can release the latter rapidly under controllable conditions with the use of heterogeneous catalyst systems. In this work, we synthesized a Ni–CoP catalyst by electrodeposition in a three-step process on carbon paper as support. The materials were characterized via SEM-EDS, XRD, and XPS techniques, while the hydrogen evolution reaction (HER) from alkaline NaBH 4 solutions was tested as a batch experiment. Ni–CoP catalyst showed a high amount of H 2 generated in a short time (∼550 mL in 1 min) and remained at 78 and 54% of its initial performance after respectively 100 and 300 h of a continuous hydrolysis process. Our catalyst revealed exceptional performance and stability at higher temperatures and a long process time, which have been a rare subject of investigation in other reports for NaBH 4 hydrolysis in the past. This work paves a new perspective in studying catalysts for hydrogen generation from borohydrides. [Display omitted] • Ni–CoP catalyst was electrodeposited on a carbon support. • Material characterization proved the formation of desired active layers. • High efficiency and stability of the catalyst for a long-term NaBH 4 hydrolysis was revealed. [ABSTRACT FROM AUTHOR]

Currently, two-dimensional (2D) layered transition metal chalcogenides (TMCs), especially MoS2, are attracting widespread attention in the field of water electrolysis. Unfortunately, the catalytic activity of MoS2 is limited to a few edge sites and by its low conductivity. Herein, MoS2/NiS heterostructures possessing a flower-like morphology were constructed via an accurate thermal treatment process to realize precise interface modification. As expected, through the adjunction of a certain amount of polyvinylpyrrolidone, NiS grew uniformly on the surface of MoS2 nanosheets, thereby forming a large number of visual lattice fringes with a specific interplanar spacing, which promoted a higher electron-transfer efficiency. The better electron-transfer efficiency resulted in a better hydrogen evolution reaction performance, providing an overpotential of 158 mV at 10 mA cm−1, a Tafel slope of 128.1 mV dec−1, and significantly long-term durability. Moreover, density functional theory calculation also showed that the precise interface modification of MoS2/NiS heterostructure exhibited more occupations at the Fermi level, which improved the electrical conductivity. Additionally, the MoS2/NiS catalysts achieved a moderately lower hydrogen adsorption energy (ΔGH*), indicating that it had better catalytic hydrogen evolution performance. This work can be extended to design other catalytic materials and for understanding reactions in the fields of energy conversion through theoretical calculations. [ABSTRACT FROM AUTHOR]

Photocatalytic water splitting is a promising approach to convert solar energy into storable hydrogen fuel. In theory, the optimization of light-harvesting and catalytic molecular conversion ability is necessary for high-efficiency hydrogen evolution; however, the establishment of a photocatalytic system composed of a light-harvesting center and an active center is limited by poor light absorption capacity, high overpotential for catalytic conversion, as well as the low efficiency of charge transfer between the two components. In this work, we demonstrate that a high-efficiency photocatalytic system consisting of two-dimensional carbon nitride (2D-C3N4) as the light-harvester and nickel sulfide (NiSx) as the active component can serve as an efficient catalyst for hydrogen evolution, wherein the tight interface formed using two-step solvothermal treatment bridges the charge transfer. The 2D structure of 2D-C3N4 can shorten the charge migration distance from the bulk to the contact interface with NiSx and minimize the charge recombination in the light-harvesting center. NiSx with a highly active surface can capture the photo-generated electrons through a tight contact interface, completing the conversion from H+ to H2. As a result, the hydrogen evolution rate of the optimal NiSx/2D-C3N4 catalyst achieves a high value of ∼4640 μmol g−1 h−1 under visible light irradiation, which is more active than most of the Pt-free 2D-C3N4 supported photocatalysts under the same reaction conditions. [ABSTRACT FROM AUTHOR]

• A simple method for synthesizing pCdS/Cu 2 O/g-C 3 N 4 composites is presented. • This work provides a new insight into the catalyst design. • Ciprofloxacin degradation reaction was over 18 times faster than pure g-C 3 N 4. • Hydrogen generation was over 18.4 times higher than pure g-C 3 N 4. • Hydrogen generation was comparable with recent publications in leading journals. We develop facile hydrothermal and precipitation approaches to fabricate porous CdS (pCdS) nanoparticles on octahedral Cu 2 O (1 1 1) microcrystals on C 3 N 4 and thus enabling to build novel pCdS/Cu 2 O/g-C 3 N 4 dual p-n Junctions. This dual p-n Junction structure would enhance charge carrier separation and transfer ability for achieving highly efficient photo/catalysis, which is much better than individual g-C 3 N 4 or pCdS/Cu 2 O p-n junctions. The degradation of ciprofloxacin (CIP) using pCdS/Cu 2 O/g-C 3 N 4 composites as a catalyst will make the reaction remarkably faster (over 18 times) than pure g-C 3 N 4. Its photocatalytic effect is well demonstrated through water splitting under simulated sunlight irradiation, where the hydrogen generation rate of 1.84 mmol h−1 g−1, i.e. over 18.40 times higher than pure g-C 3 N 4 , is achieved benefiting from its higher charge separation rate. This work provides not only a new insight into the catalyst design but also offer a stable and reusable pCdS/Cu 2 O/g-C 3 N 4 dual p-n Junctions composite as a highly efficient catalyst for use in environmental rumination and hydrogen generation. The comparison of the photocatalytic hydrogen production performance of the presented photocatalyst with some recent papers published especially in leading journals in this field proves further its significant advancement in this field. [ABSTRACT FROM AUTHOR]