Developing non-noble metal catalysts with superior catalytic activity and excellent durability is critically essential to promote electrochemical water splitting for hydrogen production. Morphology control as a promising and effective strategy is widely implemented to change the surface atomic coordination and thus enhance the intrinsic catalytic performance of current electrocatalysts. Herein, a series of cobalt phosphide (CoP) electrocatalysts with tunable morphologies of nanosheets, nanowires, nanorods, and nanoblocks have been prepared for the enhanced hydrogen evolution reaction (HER) by only adjusting the amount of ammonium fluoride (NH 4 F) in the hydrothermal process. Benefiting from the large active area, high surface activity, and favorable ion and gas diffusion channels, the clustered CoP nanorods obtained at a concentration of 0.15 M NH 4 F show the best HER performance with only an overpotential of 71 mV at a current density of 10 mA cm −2 and a low Tafel slope of 60.75 mV dec −1 in 1 M KOH. After 3000 CV cycles and 24 h durability tests, there is only a very slight degradation of performance owing to its outstanding stability and robust substrate adhesion.
Electrochemical oxidation of copper and aluminium using alternating current of industrial frequency results in the formation of non-equilibrium products. Their transformations during the ageing in sodium chloride solutions of different concentrations have been considered. According to X-Ray diffraction confirmed by TG/DSC/DTG analysis, irrespective of solution concentration, the ageing products consist of aluminium oxyhydroxide (boehmite, AlOOH), copper-aluminium carbonate hydroxide hydrate (Cu-Al/LDH) and copper chloride hydroxide (Cu[2](OH)[3]Cl). The increase of the solution concentration leads to Cu[2](OH)[3]Cl formation and makes difficulties for metal oxide carbonization to Cu-Al/LDH. Ageing in highly diluted solution contributes not only to Cu-Al/LDH formation but also boehmite hydration that is verified by IR-spectra. The pore structure characteristics have been also discussed. They do not significantly depend on phase composition and vary in ranges of 161.2-172.6 m{2}/g (specific surface areas), 0.459-0.535 cm{2}/g (total pore volumes). Pore size distributions reveal that a pore structure is predominantly formed by pore with the sizes from 3 to 22°nm; 3.6°nm is the size of pores with the largest pore volume
Developing efficient and low‐cost electrocatalysts toward oxygen evolution reaction (OER) has been one of the key research topics for overall water splitting due to the increasing demand for regenerated and clean energy. Herein, we report Ni2P@NiFe LDH hierarchical heterostructures in‐situ grown on nickel foam with good conductivity, strong substrate adhesion, special interface engineering and synergistic effects, which enables superior OER performance with a low overpotential of 204 mV at 10 mA cm−2 and a small Tafel slope of 33 mV dec−1 in 1 M KOH solution. This peculiar hierarchical hybrid electrode also possesses excellent electrochemical stability and long‐term durability at the current density of 50 mA cm−2 in an alkaline medium. More importantly, the proposed synthetic strategy of hierarchical heterostructures in this work will provide a general path to the preparation of various metal hydroxide catalysts for highly efficient OER.
MoS2@ZnO nanoheterostructures were synthesized by electrospark erosion of zinc granules in a hydrogen peroxide solution and simultaneous addition of MoS2 nanostructured powder into the reaction zone. The morphology, size of the crystallites, as well as elemental and phase composition of the prepared structures, were examined using transmission electron microscopy and X-ray diffraction analysis. It was found that the synthesized products represent heterostructures containing MoS2 nanoparticles formed on ZnO nanoparticles. Raman spectroscopy and photoluminescence analysis were also used for characterization of the prepared heterostructures. The obtained MoS2@ZnO nanostructures revealed an intense broad emission band ranging from 425 to 625 nm for samples with different fractions of MoS2. Photocatalytic measurements showed that the maximal hydrogen evolution rate of the prepared nanoheterostructures was about 906.6 μmol·g−1·h−1. The potential of their application in photocatalytic water splitting was also estimated.
The porous structure of nanoparticles of copper-cadmium oxide system prepared by AC electrochemical synthesis in sodium chloride with a concentration of 3, 15, 25 wt. % has been studied. The obtained data indicate that at a higher current density and sodium chloride concentration of 3% wt. in the electrochemical oxidation of cadmium and copper products are formed with the structure of mesopores and channels. In this case, the specific surface area has the greatest value (19.4 m{2}/g) and a maximum pore volume (0.0778 cm{3}/g). Thus, the obtained data allow predicting the operating parameters of the electrolysis to obtain a copper - cadmium oxide system of a predetermined porous structure
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.